$126+ Cheap flights from Washington to Illinois
This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 9/18. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — ORD
Jul 23 — Jul 301
Round-trip
1 adult, Economy
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Find cheap flights from Washington to Illinois with Cheapflights
1. Tell us where you want to go
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Cheapest flights from Washington to IllinoisExplore the most affordable flight options available from Washington to Illinois. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 23, 2026.
Explore the most affordable flight options available from Washington to Illinois. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 23, 2026.
This Frontier deal was found by Cheapflights users on 6/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/119:34 pm
PDX
- STL
1 stop12h 17m
Frontier
Sun 9/1312:46 pm
STL
- PDX
1 stop9h 53m
Frontier
Deal found 6/23![Frontier logo]()
$240
This CheapOair deal was found by Cheapflights users on 6/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/145:16 pm
PDX
- STL
1 stop24h 07m
Frontier
Tue 7/218:08 pm
STL
- PDX
1 stop22h 28m
Frontier
Deal found 6/23![Frontier logo]()
$250
This Kiwi.com deal was found by Cheapflights users on 6/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/1112:34 pm
PDX
- STL
1 stop28h 41m
Frontier
Tue 10/208:10 pm
STL
- PDX
1 stop22h 25m
Frontier
Deal found 6/18![Frontier logo]()
$261
This CheapOair deal was found by Cheapflights users on 6/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 7/65:49 pm
PDX
- STL
1 stop22h 16m
Frontier
Thu 7/98:08 pm
STL
- PDX
1 stop22h 43m
Frontier
Deal found 6/22![Frontier logo]()
$268
This CheapOair deal was found by Cheapflights users on 6/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/125:21 pm
PDX
- STL
1 stop24h 02m
Frontier
Sun 8/167:10 pm
STL
- PDX
1 stop23h 44m
Frontier
Deal found 6/21![Frontier logo]()
$275
This Frontier deal was found by Cheapflights users on 6/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/189:34 pm
PDX
- STL
1 stop12h 17m
Frontier
Mon 9/2112:46 pm
STL
- PDX
1 stop9h 53m
Frontier
Deal found 6/23![Frontier logo]()
$276
This CheapOair deal was found by Cheapflights users on 6/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/175:49 pm
PDX
- STL
1 stop22h 26m
Frontier
Tue 7/218:08 pm
STL
- PDX
1 stop22h 28m
Frontier
Deal found 6/18![Frontier logo]()
$285
This CheapOair deal was found by Cheapflights users on 6/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/145:49 pm
PDX
- STL
1 stop22h 26m
Frontier
Sat 8/296:45 pm
STL
- PDX
1 stop20h 07m
Frontier
Deal found 6/21![Frontier logo]()
$286
This CheapOair deal was found by Cheapflights users on 6/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/145:16 pm
PDX
- STL
1 stop24h 07m
Frontier
Thu 7/167:10 pm
STL
- PDX
1 stop23h 44m
Frontier
Deal found 6/23![Frontier logo]()
$289
This CheapOair deal was found by Cheapflights users on 6/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/85:21 pm
PDX
- STL
1 stop24h 02m
Frontier
Tue 7/148:08 pm
STL
- PDX
1 stop22h 28m
Frontier
Deal found 6/21![Frontier logo]()
$294
This American Airlines deal was found by Cheapflights users on 6/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/122:27 pm
GEG
- ORD
Nonstop4h 01m
American Airlines
Wed 9/211:30 am
ORD
- GEG
Nonstop4h 07m
American Airlines
Deal found 6/20![American Airlines logo]()
$297
This CheapOair deal was found by Cheapflights users on 6/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/75:16 pm
PDX
- STL
1 stop24h 07m
Frontier
Thu 7/97:10 pm
STL
- PDX
1 stop23h 44m
Frontier
Deal found 6/20![Frontier logo]()
$298
Best flights from Washington to IllinoisDiscover carefully curated flight deals from Washington to Illinois that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated June 23, 2026.
Discover carefully curated flight deals from Washington to Illinois that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated June 23, 2026.
This Delta deal was found by Cheapflights users on 6/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/125:15 am
GEG
- ORD
1 stop6h 08m
Delta
Wed 9/29:30 am
ORD
- GEG
1 stop8h 06m
Delta
Deal found 6/19![Delta logo]()
$317
This Southwest deal was found by Cheapflights users on 6/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/2710:45 pm
PDX
- STL
1 stop10h 50m
Southwest
Sat 8/292:15 pm
STL
- PDX
1 stop6h 10m
Southwest
Deal found 6/18![Southwest logo]()
$319
This United Airlines deal was found by Cheapflights users on 6/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/310:45 am
PDX
- ORD
Nonstop4h 04m
United Airlines
Sat 11/74:20 pm
ORD
- PDX
1 stop6h 48m
United Airlines
Deal found 6/20![United Airlines logo]()
$335
This Alaska Airlines deal was found by Cheapflights users on 6/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/94:38 pm
GEG
- ORD
1 stop11h 42m
Alaska Airlines
Tue 10/136:00 am
ORD
- GEG
1 stop7h 39m
Alaska Airlines
Deal found 6/22![Alaska Airlines logo]()
$338
This Delta deal was found by Cheapflights users on 6/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 11/63:10 pm
PDX
- STL
1 stop6h 08m
Delta
Mon 11/97:55 pm
STL
- PDX
1 stop5h 56m
Delta
Deal found 6/20![Delta logo]()
$319
This Southwest deal was found by Cheapflights users on 6/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/1511:30 pm
PDX
- STL
1 stop7h 45m
Southwest
Sat 8/228:25 am
STL
- PDX
2 stops11h 15m
Southwest
Deal found 6/21![Southwest logo]()
$324
This Alaska Airlines deal was found by Cheapflights users on 6/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/148:15 am
GEG
- ORD
1 stop8h 42m
Alaska Airlines
Sat 8/157:17 pm
ORD
- GEG
1 stop6h 42m
Alaska Airlines
Deal found 6/20![Alaska Airlines logo]()
$338
This United Airlines deal was found by Cheapflights users on 6/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/242:27 pm
PDX
- ORD
Nonstop4h 13m
United Airlines
Mon 8/317:00 am
ORD
- PDX
Nonstop4h 29m
United Airlines
Deal found 6/22![United Airlines logo]()
$351
This Southwest deal was found by Cheapflights users on 6/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/1511:30 pm
PDX
- MDW
Nonstop3h 55m
Southwest
Tue 9/228:55 pm
MDW
- PDX
Nonstop4h 15m
Southwest
Deal found 6/19![Southwest logo]()
$325
This Delta deal was found by Cheapflights users on 6/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/226:45 am
GEG
- ORD
1 stop6h 45m
Delta
Thu 8/273:25 pm
ORD
- GEG
2 stops10h 28m
Delta
Deal found 6/21![Delta logo]()
$334
This Alaska Airlines deal was found by Cheapflights users on 6/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/155:48 pm
SEA
- ORD
Nonstop4h 11m
Alaska Airlines
Sat 7/258:20 pm
ORD
- SEA
Nonstop4h 44m
Alaska Airlines
Deal found 6/18![Alaska Airlines logo]()
$355
This Southwest deal was found by Cheapflights users on 6/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 7/1811:30 pm
PDX
- MDW
Nonstop3h 50m
Southwest
Sat 7/258:25 pm
MDW
- PDX
Nonstop4h 25m
Southwest
Deal found 6/22![Southwest logo]()
$325
This United Airlines deal was found by Cheapflights users on 6/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/243:55 pm
SEA
- ORD
1 stop6h 04m
United Airlines
Sun 9/277:00 am
ORD
- SEA
Nonstop4h 38m
United Airlines
Deal found 6/18![United Airlines logo]()
$358
This Delta deal was found by Cheapflights users on 6/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/1711:43 am
GEG
- MDW
1 stop9h 02m
Delta
Mon 9/216:05 am
MDW
- GEG
1 stop7h 23m
Delta
Deal found 6/23![Delta logo]()
$341
This Alaska Airlines deal was found by Cheapflights users on 6/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/2910:29 am
SEA
- ORD
Nonstop4h 15m
Alaska Airlines
Mon 8/33:43 pm
ORD
- SEA
Nonstop4h 39m
Alaska Airlines
Deal found 6/21![Alaska Airlines logo]()
$356
This Southwest deal was found by Cheapflights users on 6/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/1210:45 pm
PDX
- STL
1 stop10h 50m
Southwest
Wed 8/195:35 am
STL
- PDX
2 stops11h 50m
Southwest
Deal found 6/19![Southwest logo]()
$330
This United Airlines deal was found by Cheapflights users on 6/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/710:43 am
PDX
- ORD
1 stop6h 46m
United Airlines
Sun 10/117:00 am
ORD
- PDX
Nonstop4h 31m
United Airlines
Deal found 6/22![United Airlines logo]()
$367
This Delta deal was found by Cheapflights users on 6/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/147:30 pm
GEG
- MDW
2 stops11h 37m
Delta
Mon 9/216:05 am
MDW
- GEG
1 stop7h 23m
Delta
Deal found 6/23![Delta logo]()
$346
This Alaska Airlines deal was found by Cheapflights users on 6/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 7/1312:17 am
SEA
- ORD
Nonstop4h 03m
Alaska Airlines
Wed 7/226:00 am
ORD
- SEA
Nonstop4h 38m
Alaska Airlines
Deal found 6/19![Alaska Airlines logo]()
$357
This Southwest deal was found by Cheapflights users on 6/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/511:30 pm
PDX
- MDW
Nonstop3h 55m
Southwest
Wed 8/1212:00 pm
MDW
- PDX
2 stops9h 50m
Southwest
Deal found 6/22![Southwest logo]()
$340
This United Airlines deal was found by Cheapflights users on 6/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/311:11 pm
SEA
- STL
1 stop7h 28m
United Airlines
Mon 8/101:13 pm
STL
- SEA
1 stop7h 53m
United Airlines
Deal found 6/21![United Airlines logo]()
$379
This Delta deal was found by Cheapflights users on 6/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/177:30 pm
GEG
- ORD
2 stops10h 27m
Delta
Mon 9/215:10 pm
ORD
- GEG
2 stops8h 47m
Delta
Deal found 6/23![Delta logo]()
$351
This Alaska Airlines deal was found by Cheapflights users on 6/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/197:01 am
SEA
- ORD
1 stop9h 52m
Alaska Airlines
Sun 10/259:00 am
ORD
- SEA
Nonstop4h 44m
Alaska Airlines
Deal found 6/20![Alaska Airlines logo]()
$358
This United Airlines deal was found by Cheapflights users on 6/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/311:40 pm
PDX
- ORD
Nonstop4h 05m
United Airlines
Thu 8/65:00 am
ORD
- PDX
1 stop6h 47m
United Airlines
Deal found 6/22![United Airlines logo]()
$380
This Southwest deal was found by Cheapflights users on 6/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/272:05 pm
PDX
- STL
1 stop7h 00m
Southwest
Sun 8/309:55 pm
STL
- PDX
Nonstop4h 10m
Southwest
Deal found 6/18![Southwest logo]()
$348
This Delta deal was found by Cheapflights users on 6/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/291:45 pm
PDX
- ORD
1 stop5h 48m
Delta
Thu 10/156:59 pm
ORD
- PDX
1 stop6h 52m
Delta
Deal found 6/22![Delta logo]()
$358
This Alaska Airlines deal was found by Cheapflights users on 6/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/2412:17 am
SEA
- ORD
Nonstop4h 03m
Alaska Airlines
Tue 7/287:59 pm
ORD
- SEA
1 stop15h 20m
Alaska Airlines
Deal found 6/21![Alaska Airlines logo]()
$367
This United Airlines deal was found by Cheapflights users on 6/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/187:02 am
PDX
- ORD
Nonstop4h 13m
United Airlines
Sun 9/208:50 am
ORD
- PDX
Nonstop4h 38m
United Airlines
Deal found 6/19![United Airlines logo]()
$389
This Southwest deal was found by Cheapflights users on 6/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/2411:30 pm
PDX
- MDW
Nonstop3h 55m
Southwest
Mon 8/319:00 am
MDW
- PDX
1 stop8h 00m
Southwest
Deal found 6/22![Southwest logo]()
$357
This Delta deal was found by Cheapflights users on 6/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/95:45 pm
SEA
- ORD
Nonstop4h 01m
Delta
Mon 10/127:30 am
ORD
- SEA
1 stop6h 54m
Delta
Deal found 6/22![Delta logo]()
$363
Last-minute flights from Washington to IllinoisDiscover last-minute flight deals from Washington to Illinois. Data last updated June 23, 2026 and is based on user searches.
Discover last-minute flight deals from Washington to Illinois. Data last updated June 23, 2026 and is based on user searches.
This CheapOair deal was found by Cheapflights users on 6/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 7/65:49 pm
PDX
- STL
1 stop22h 16m
Frontier
Thu 7/98:08 pm
STL
- PDX
1 stop22h 43m
Frontier
Deal found 6/22![Frontier logo]()
$268
This CheapOair deal was found by Cheapflights users on 6/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/75:16 pm
PDX
- STL
1 stop24h 07m
Frontier
Thu 7/97:10 pm
STL
- PDX
1 stop23h 44m
Frontier
Deal found 6/20![Frontier logo]()
$298
This CheapOair deal was found by Cheapflights users on 6/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/85:21 pm
PDX
- STL
1 stop24h 02m
Frontier
Tue 7/148:08 pm
STL
- PDX
1 stop22h 28m
Frontier
Deal found 6/21![Frontier logo]()
$294
This CheapOair deal was found by Cheapflights users on 6/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/105:49 pm
PDX
- STL
1 stop22h 26m
Frontier
Sat 7/188:08 pm
STL
- PDX
1 stop22h 43m
Frontier
Deal found 6/19![Frontier logo]()
$315
This American Airlines deal was found by Cheapflights users on 6/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/1011:15 pm
PDX
- STL
1 stop7h 16m
American Airlines
Sat 7/187:24 pm
STL
- PDX
1 stop7h 31m
American Airlines
Deal found 6/19![American Airlines logo]()
$319
This CheapOair deal was found by Cheapflights users on 6/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/145:16 pm
PDX
- STL
1 stop24h 07m
Frontier
Thu 7/167:10 pm
STL
- PDX
1 stop23h 44m
Frontier
Deal found 6/23![Frontier logo]()
$289
This American Airlines deal was found by Cheapflights users on 6/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/152:29 pm
GEG
- ORD
Nonstop4h 03m
American Airlines
Tue 7/285:00 am
ORD
- GEG
1 stop8h 59m
American Airlines
Deal found 6/21![American Airlines logo]()
$307
This United Airlines deal was found by Cheapflights users on 6/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/1511:40 pm
PDX
- STL
1 stop6h 59m
United Airlines
Thu 7/167:23 pm
STL
- PDX
1 stop7h 27m
United Airlines
Deal found 6/19![United Airlines logo]()
$314
This Delta deal was found by Cheapflights users on 6/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/155:25 am
GEG
- ORD
1 stop9h 18m
Delta
Sat 7/185:55 pm
ORD
- GEG
1 stop7h 03m
Delta
Deal found 6/22![Delta logo]()
$317
This CheapOair deal was found by Cheapflights users on 6/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/175:49 pm
PDX
- STL
1 stop22h 26m
Frontier
Tue 7/218:08 pm
STL
- PDX
1 stop22h 28m
Frontier
Deal found 6/18![Frontier logo]()
$285
This American Airlines deal was found by Cheapflights users on 6/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/292:29 pm
GEG
- ORD
Nonstop4h 03m
American Airlines
Tue 8/411:30 am
ORD
- GEG
Nonstop4h 09m
American Airlines
Deal found 6/22![American Airlines logo]()
$297
This CheapOair deal was found by Cheapflights users on 6/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 7/306:49 pm
PDX
- STL
1 stop21h 26m
Frontier
Fri 8/78:08 pm
STL
- PDX
1 stop22h 43m
Frontier
Deal found 6/23![Frontier logo]()
$250
One-way flights from Washington to IllinoisSearch for one-way flight options from Washington to Illinois. Find affordable one-way fares based on user searches. Data last updated June 23, 2026.
Search for one-way flight options from Washington to Illinois. Find affordable one-way fares based on user searches. Data last updated June 23, 2026.
This Expedia deal was found by Cheapflights users on 6/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/189:34 pm
PDX
- STL
1 stop12h 17m
Frontier
Deal found 6/21![Frontier logo]()
$126
This Trip.com deal was found by Cheapflights users on 6/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 7/236:49 pm
PDX
- STL
1 stop21h 26m
Frontier
Deal found 6/23![Frontier logo]()
$129
This Trip.com deal was found by Cheapflights users on 6/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/295:21 pm
PDX
- STL
1 stop24h 02m
Frontier
Deal found 6/20![Frontier logo]()
$130
This CheapOair deal was found by Cheapflights users on 6/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/175:49 pm
PDX
- STL
1 stop22h 26m
Frontier
Deal found 6/21![Frontier logo]()
$131
This Trip.com deal was found by Cheapflights users on 6/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/85:21 pm
PDX
- STL
1 stop24h 02m
Frontier
Deal found 6/21![Frontier logo]()
$138
This CheapOair deal was found by Cheapflights users on 6/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/105:49 pm
PDX
- STL
1 stop22h 26m
Frontier
Deal found 6/22![Frontier logo]()
$140
This American Airlines deal was found by Cheapflights users on 6/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/42:29 pm
GEG
- ORD
Nonstop4h 03m
American Airlines
Deal found 6/19![American Airlines logo]()
$149
This Frontier deal was found by Cheapflights users on 6/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/169:16 pm
SEA
- STL
1 stop12h 35m
Frontier
Deal found 6/21![Frontier logo]()
$151
This Alaska Airlines deal was found by Cheapflights users on 6/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/188:15 am
GEG
- ORD
1 stop8h 42m
Alaska Airlines
Deal found 6/18![Alaska Airlines logo]()
$151
This Kiwi.com deal was found by Cheapflights users on 6/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/69:14 pm
GEG
- STL
1 stop19h 01m
Multiple Airlines
Deal found 6/18![Multiple Airlines logo]()
$152
This United Airlines deal was found by Cheapflights users on 6/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/67:00 am
PDX
- STL
1 stop9h 39m
United Airlines
Deal found 6/22![United Airlines logo]()
$155
This Kiwi.com deal was found by Cheapflights users on 6/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/188:53 pm
SEA
- STL
1 stop18h 57m
Frontier
Deal found 6/22![Frontier logo]()
$156
Find flight deals from Washington to Illinois
Keep the following information in mind while searching for Washington to Illinois flight deals. Data was last updated June 23, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $240 (Frontier) |
One-way from | $126 (Expedia) |
Popular in | June |
Cheapest in | February |
Average price | $413 |
Good round-trip deal | $379 or less |
Good one-way deal | $204 or less |
Cheapflights Fare Finder
Customize your flight search to find flights from Washington to Illinois that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated June 23, 2026.
Use the filters below to find and compare flights from Washington to Illinois that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
SpokaneChicago
GEG - ORD
GEGORD
Spokane
Wed 8/12
5:15 am-1:23 pm
1 stop6h 08m
Chicago O'Hare Intl
Wed 9/2
9:30 am-3:36 pm
1 stop8h 06m
$317
PortlandSt. Louis
PDX - STL
PDXSTL
Portland
Thu 8/27
10:45 pm-11:35 am
1 stop10h 50m
Lambert-St Louis
Sat 8/29
2:15 pm-6:25 pm
1 stop6h 10m
$319
PortlandSt. Louis
PDX - STL
PDXSTL
Portland
Fri 11/6
3:10 pm-11:18 pm
1 stop6h 08m
Lambert-St Louis
Mon 11/9
7:55 pm-11:51 pm
1 stop5h 56m
$319
PortlandSt. Louis
PDX - STL
PDXSTL
Portland
Sat 8/15
11:30 pm-9:15 am
1 stop7h 45m
Lambert-St Louis
Sat 8/22
8:25 am-5:40 pm
2 stops11h 15m
$324
Quickest round-trip
PortlandChicago
PDX - MDW
PDXMDW
Portland
Tue 9/15
11:30 pm-5:25 am
Nonstop3h 55m
Chicago Midway
Tue 9/22
8:55 pm-11:10 pm
Nonstop4h 15m
$325
PortlandChicago
PDX - MDW
PDXMDW
Portland
Sat 7/18
11:30 pm-5:20 am
Nonstop3h 50m
Chicago Midway
Sat 7/25
8:25 pm-10:50 pm
Nonstop4h 25m
$325
PortlandSt. Louis
PDX - STL
PDXSTL
Portland
Wed 8/12
10:45 pm-11:35 am
1 stop10h 50m
Lambert-St Louis
Wed 8/19
5:35 am-3:25 pm
2 stops11h 50m
$330
SpokaneChicago
GEG - ORD
GEGORD
Spokane
Sat 8/22
6:45 am-3:30 pm
1 stop6h 45m
Chicago O'Hare Intl
Thu 8/27
3:25 pm-11:53 pm
2 stops10h 28m
$334
PortlandChicago
PDX - ORD
PDXORD
Portland
Tue 11/3
10:45 am-4:49 pm
Nonstop4h 04m
Chicago O'Hare Intl
Sat 11/7
4:20 pm-9:08 pm
1 stop6h 48m
$335
SpokaneChicago
GEG - ORD
GEGORD
Spokane
Fri 10/9
4:38 pm-6:20 am
1 stop11h 42m
Chicago O'Hare Intl
Tue 10/13
6:00 am-11:39 am
1 stop7h 39m
$338
Showing 1-10 of 60 resultsSorted by cheapest first
Best time to book a flight from Washington to Illinois
Have a flexible travel schedule? Discover the best time to fly to Illinois from Washington with our price prediction graph.
PDX-STL
GEG-ORD
PDX-ORD
PDX-MDW
SEA-ORD
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.
Cheapflights Insights
Everything you need to know about your flight from Washington to Illinois
USWA-USIL
PDX-STL
GEG-ORD
PDX-ORD
PDX-MDW
What is the cheapest month to book a flight from State of Washington to Illinois?
Currently, January is the cheapest month in which you can book a flight from State of Washington to Illinois (average of $47). Flying from State of Washington to Illinois in March is currently the most expensive (average of $532). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.
What is the cheapest time of day to fly from WA to IL?
Find hourly flight availability from Washington to Illinois. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated June 23, 2026.
When flying from State of Washington to Illinois, the time of day you fly usually plays a role in the price. Save by searching for a flight at noon, which can drop the price by up to 19% versus a flight in the evening.
Weekly flight availability from State of Washington to Illinois
Explore weekly flight availability from Washington to Illinois. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated June 23, 2026.
The most flights from USWA to USIL are scheduled on a Monday (65 on average). You will have fewer flight options on Thursday, which is when the least amount of flights are scheduled (52 on average).
How much does it cost to fly round-trip from State of Washington to Illinois?
How far ahead should I book a flight from State of Washington to Illinois?
To ensure you get the cheapest price possible for a flight from State of Washington to Illinois, you should look to book at least 81 days in advance of your intended travel date. The price of your flight may increase if you delay and leave booking until a week or so before departure.
What is the cheapest day to fly from State of Washington to Illinois?
Use this chart to determine the cheapest time to fly round-trip from Washington to Illinois. Price data was last updated on June 20, 2026.
Travelers seeking maximum savings on their State of Washington to Illinois flight should consider departing on Saturday afternoons when fares are most often at their lowest. Sunday evenings flights should be avoided if possible as fares are typically the most expensive at this time.
Reviews of airlines servicing Illinois
Get insights into the airlines that provide service to Illinois. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Illinois. Reviews last updated June 23, 2026.
Get a feel of what it's like to fly with Alaska Airlines,Southwest, andDelta from Washington to Illinois by reading reviews from past customers. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Overall
7.9
Entertainment
7.0
Food
7.0
Crew
8.5
Boarding
8.1
Comfort
7.8
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Overall
7.9
Entertainment
7.0
Food
7.0
Crew
8.5
Boarding
8.1
Comfort
7.8
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Overall
7.9
Entertainment
7.0
Food
7.0
Crew
8.5
Boarding
8.1
Comfort
7.8
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Overall
7.9
Entertainment
7.0
Food
7.0
Crew
8.5
Boarding
8.1
Comfort
7.8
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Overall
7.9
Entertainment
7.0
Food
7.0
Crew
8.5
Boarding
8.1
Comfort
7.8
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Overall
7.9
Entertainment
7.0
Food
7.0
Crew
8.5
Boarding
8.1
Comfort
7.8
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Related info for your journey
Find useful and relevant information for your journey from Washington to Illinois. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
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Alternative routes for Washington to Illinois
See prices for flight routes from nearby airports that may be better suited for you.
Complete your trip
Complete your trip to Illinois by adding a car rental and/or hotel reservation to your travel itinerary.
Search flights from Washington to Illinois by cabin class
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Washington and Illinois flights
Browse other Washington and Illinois flight options. Last updated on June 23, 2026.
Popular flight searches
Check out other popular destinations found by fellow travelers in 2026
Find a return flight route from Illinois
Find the right flight back to Washington after your stay in Illinois
Washington to Illinois flights
Consider these flights traveling from Washington to Illinois.
Top 7 airlines flying from Washington to Illinois
Discover the top 7 airlines that operate flights from Washington to Illinois. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated June 23, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$123 | Average$399 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$124 | Average$249 | FlexibilityNo cancel fee | On-time85% | |
| Cheapest$177 | Average$447 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$177 | Average$431 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$180 | Average$404 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$193 | Average$313 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$219 | Average$387 | FlexibilityNo cancel fee | On-time63% |