$101+ Cheap flights from Illinois to Washington
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 5/27. Fares are subject to change and may not be available on all flights or dates of travel.
ORD — SEA
May 29 — Jun 51
Round-trip
1 adult, Economy
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Cheapest flights from Illinois to WashingtonExplore the most affordable flight options available from Illinois to Washington. Find the lowest fares from popular airlines and budget airlines, with prices last updated on April 29, 2026.
Explore the most affordable flight options available from Illinois to Washington. Find the lowest fares from popular airlines and budget airlines, with prices last updated on April 29, 2026.
This Kiwi.com deal was found by Cheapflights users on 4/28. 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.
Wed 5/278:08 pm
STL
- SEA
1 stop19h 53m
Frontier
Fri 6/57:50 pm
SEA
- STL
1 stop21h 33m
Frontier
Deal found 4/28![Frontier logo]()
$230
This Kiwi.com deal was found by Cheapflights users on 4/24. 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 5/268:08 pm
STL
- SEA
1 stop15h 58m
Frontier
Fri 5/297:50 pm
SEA
- STL
1 stop21h 33m
Frontier
Deal found 4/24![Frontier logo]()
$233
This Booking.com deal was found by Cheapflights users on 4/24. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 5/129:37 pm
ORD
- SEA
1 stop14h 12m
Frontier
Thu 5/147:50 pm
SEA
- ORD
1 stop22h 42m
Frontier
Deal found 4/24![Frontier logo]()
$239
This CheapOair deal was found by Cheapflights users on 4/24. 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 5/128:00 am
ORD
- SEA
Nonstop4h 40m
Alaska Airlines
Sat 5/165:42 pm
SEA
- ORD
Nonstop4h 17m
Alaska Airlines
Deal found 4/24![Alaska Airlines logo]()
$240
This Trip.com deal was found by Cheapflights users on 4/26. 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 5/79:37 pm
ORD
- SEA
1 stop14h 12m
Frontier
Mon 5/117:50 pm
SEA
- ORD
1 stop22h 42m
Frontier
Deal found 4/26![Frontier logo]()
$242
This Trip.com deal was found by Cheapflights users on 4/25. 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.
Fri 5/89:37 pm
ORD
- SEA
1 stop14h 12m
Frontier
Mon 5/117:50 pm
SEA
- ORD
1 stop22h 42m
Frontier
Deal found 4/25![Frontier logo]()
$243
This Trip.com deal was found by Cheapflights users on 4/27. 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.
Fri 5/88:08 pm
STL
- SEA
1 stop15h 41m
Frontier
Fri 5/157:50 pm
SEA
- STL
1 stop21h 33m
Frontier
Deal found 4/27![Frontier logo]()
$243
This Trip.com deal was found by Cheapflights users on 4/24. 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.
Tue 5/129:37 pm
ORD
- SEA
1 stop14h 12m
Frontier
Thu 5/2811:21 am
SEA
- ORD
1 stop17h 13m
Frontier
Deal found 4/24![Frontier logo]()
$244
This Kiwi.com deal was found by Cheapflights users on 4/28. 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 5/268:08 pm
STL
- SEA
2 stops48h 57m
Frontier
Wed 6/37:50 pm
SEA
- STL
1 stop21h 33m
Frontier
Deal found 4/28![Frontier logo]()
$246
This Trip.com deal was found by Cheapflights users on 4/28. 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.
Sat 5/98:08 pm
STL
- SEA
1 stop15h 41m
Frontier
Mon 5/1811:37 am
SEA
- STL
1 stop28h 29m
Frontier
Deal found 4/28![Frontier logo]()
$248
This American Airlines deal was found by Cheapflights users on 4/24. 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.
Thu 5/1410:00 pm
ORD
- SEA
Nonstop4h 36m
American Airlines
Wed 5/203:17 pm
SEA
- ORD
Nonstop4h 23m
American Airlines
Deal found 4/24![American Airlines logo]()
$249
This United Airlines deal was found by Cheapflights users on 4/28. 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.
Sat 8/295:10 am
STL
- SEA
1 stop6h 53m
United Airlines
Sat 8/2911:56 pm
SEA
- STL
1 stop8h 13m
United Airlines
Deal found 4/28![United Airlines logo]()
$249
Best flights from Illinois to WashingtonDiscover carefully curated flight deals from Illinois to Washington that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated April 29, 2026.
Discover carefully curated flight deals from Illinois to Washington that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated April 29, 2026.
This Alaska Airlines deal was found by Cheapflights users on 4/27. 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 5/295:33 pm
STL
- PDX
Nonstop4h 17m
Alaska Airlines
Wed 6/310:37 am
PDX
- STL
Nonstop4h 00m
Alaska Airlines
Deal found 4/27![Alaska Airlines logo]()
$283
This Delta deal was found by Cheapflights users on 4/25. 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 5/271:59 pm
STL
- PDX
1 stop10h 03m
Delta
Mon 6/19:50 am
PDX
- STL
1 stop7h 13m
Delta
Deal found 4/25![Delta logo]()
$303
This Southwest deal was found by Cheapflights users on 4/28. 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 5/289:50 pm
MDW
- PDX
Nonstop4h 20m
Southwest
Tue 6/26:10 pm
PDX
- MDW
1 stop9h 50m
Southwest
Deal found 4/28![Southwest logo]()
$315
This United Airlines deal was found by Cheapflights users on 4/27. 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 9/25:31 pm
PIA
- SEA
1 stop7h 11m
United Airlines
Wed 9/912:29 pm
SEA
- PIA
2 stops9h 53m
United Airlines
Deal found 4/27![United Airlines logo]()
$317
This Alaska Airlines deal was found by Cheapflights users on 4/28. 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.
Sat 5/305:33 pm
STL
- PDX
Nonstop4h 17m
Alaska Airlines
Tue 6/210:37 am
PDX
- STL
Nonstop4h 00m
Alaska Airlines
Deal found 4/28![Alaska Airlines logo]()
$289
This Delta deal was found by Cheapflights users on 4/24. 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 7/297:54 pm
STL
- SEA
1 stop6h 05m
Delta
Thu 8/611:59 pm
SEA
- STL
1 stop6h 43m
Delta
Deal found 4/24![Delta logo]()
$304
This Southwest deal was found by Cheapflights users on 4/24. 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 6/38:50 pm
MDW
- PDX
Nonstop4h 20m
Southwest
Wed 6/1011:30 pm
PDX
- MDW
Nonstop3h 50m
Southwest
Deal found 4/24![Southwest logo]()
$315
This United Airlines deal was found by Cheapflights users on 4/24. 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 6/35:33 pm
PIA
- SEA
1 stop8h 26m
United Airlines
Mon 6/811:52 pm
SEA
- PIA
1 stop8h 18m
United Airlines
Deal found 4/24![United Airlines logo]()
$320
This Alaska Airlines deal was found by Cheapflights users on 4/28. 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 5/292:10 pm
ORD
- GEG
1 stop9h 35m
Alaska Airlines
Sat 6/61:59 pm
GEG
- ORD
1 stop7h 00m
Alaska Airlines
Deal found 4/28![Alaska Airlines logo]()
$295
This Delta deal was found by Cheapflights users on 4/24. 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 8/146:59 pm
STL
- SEA
1 stop7h 02m
Delta
Sat 8/225:45 am
SEA
- STL
1 stop5h 36m
Delta
Deal found 4/24![Delta logo]()
$304
This Southwest deal was found by Cheapflights users on 4/28. 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 5/289:50 pm
MDW
- PDX
Nonstop4h 20m
Southwest
Thu 6/411:30 pm
PDX
- MDW
Nonstop3h 50m
Southwest
Deal found 4/28![Southwest logo]()
$316
This Alaska Airlines deal was found by Cheapflights users on 4/26. 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.
Thu 6/49:00 am
ORD
- GEG
1 stop14h 45m
Alaska Airlines
Sat 6/61:59 pm
GEG
- ORD
1 stop8h 00m
Alaska Airlines
Deal found 4/26![Alaska Airlines logo]()
$295
This United Airlines deal was found by Cheapflights users on 4/24. 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 7/245:00 am
ORD
- PDX
1 stop6h 47m
United Airlines
Mon 7/275:00 pm
PDX
- ORD
Nonstop4h 13m
United Airlines
Deal found 4/24![United Airlines logo]()
$337
This Delta deal was found by Cheapflights users on 4/25. 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 5/297:59 pm
STL
- PDX
1 stop5h 45m
Delta
Mon 6/111:12 pm
PDX
- STL
1 stop8h 17m
Delta
Deal found 4/25![Delta logo]()
$309
This United Airlines deal was found by Cheapflights users on 4/28. 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 6/225:41 pm
STL
- SEA
1 stop6h 58m
United Airlines
Thu 6/2511:52 pm
SEA
- STL
1 stop6h 49m
United Airlines
Deal found 4/28![United Airlines logo]()
$341
This Southwest deal was found by Cheapflights users on 4/28. 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 6/272:35 pm
MDW
- PDX
1 stop7h 05m
Southwest
Sat 7/46:00 am
PDX
- MDW
Nonstop3h 50m
Southwest
Deal found 4/28![Southwest logo]()
$346
This Alaska Airlines deal was found by Cheapflights users on 4/28. 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.
Thu 6/117:20 am
ORD
- PDX
Nonstop4h 25m
Alaska Airlines
Sat 6/1310:59 pm
PDX
- ORD
Nonstop4h 01m
Alaska Airlines
Deal found 4/28![Alaska Airlines logo]()
$316
This Delta deal was found by Cheapflights users on 4/28. 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 5/267:13 pm
MDW
- GEG
1 stop5h 53m
Delta
Tue 6/210:40 pm
GEG
- MDW
1 stop9h 20m
Delta
Deal found 4/28![Delta logo]()
$317
This Alaska Airlines deal was found by Cheapflights users on 4/25. 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.
Thu 7/167:20 am
ORD
- PDX
Nonstop4h 25m
Alaska Airlines
Tue 7/2110:59 pm
PDX
- ORD
Nonstop4h 01m
Alaska Airlines
Deal found 4/25![Alaska Airlines logo]()
$316
This United Airlines deal was found by Cheapflights users on 4/28. 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 10/83:52 pm
MLI
- SEA
1 stop8h 37m
United Airlines
Sun 10/1111:50 pm
SEA
- MLI
1 stop8h 24m
United Airlines
Deal found 4/28![United Airlines logo]()
$349
This Southwest deal was found by Cheapflights users on 4/26. 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 6/69:00 pm
MDW
- SEA
Nonstop4h 30m
Southwest
Mon 6/811:05 pm
SEA
- MDW
Nonstop3h 55m
Southwest
Deal found 4/26![Southwest logo]()
$355
This Delta deal was found by Cheapflights users on 4/28. 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 6/105:30 am
ORD
- PDX
1 stop9h 30m
Delta
Fri 6/2612:33 am
PDX
- ORD
1 stop6h 02m
Delta
Deal found 4/28![Delta logo]()
$325
This United Airlines deal was found by Cheapflights users on 4/26. 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 10/166:49 pm
STL
- SEA
1 stop7h 25m
United Airlines
Mon 10/1910:40 pm
SEA
- STL
1 stop7h 57m
United Airlines
Deal found 4/26![United Airlines logo]()
$349
This Southwest deal was found by Cheapflights users on 4/28. 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 6/1110:00 pm
MDW
- SEA
Nonstop4h 30m
Southwest
Mon 6/1511:05 pm
SEA
- MDW
Nonstop3h 55m
Southwest
Deal found 4/28![Southwest logo]()
$355
This Delta deal was found by Cheapflights users on 4/25. 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 5/267:13 pm
MDW
- GEG
1 stop5h 53m
Delta
Mon 6/16:10 am
GEG
- MDW
2 stops10h 23m
Delta
Deal found 4/25![Delta logo]()
$331
This Alaska Airlines deal was found by Cheapflights users on 4/27. 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.
Sat 5/305:52 pm
ORD
- PDX
1 stop8h 07m
Alaska Airlines
Fri 6/55:46 pm
PDX
- ORD
1 stop10h 34m
Alaska Airlines
Deal found 4/27![Alaska Airlines logo]()
$336
This United Airlines deal was found by Cheapflights users on 4/28. 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.
Sat 5/307:23 pm
STL
- SEA
1 stop7h 50m
United Airlines
Thu 6/411:52 pm
SEA
- STL
1 stop6h 49m
United Airlines
Deal found 4/28![United Airlines logo]()
$349
This Southwest deal was found by Cheapflights users on 4/26. 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 5/268:50 pm
MDW
- PDX
Nonstop4h 20m
Southwest
Tue 6/26:10 pm
PDX
- MDW
1 stop9h 50m
Southwest
Deal found 4/26![Southwest logo]()
$360
This Delta deal was found by Cheapflights users on 4/25. 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 5/287:13 pm
MDW
- GEG
1 stop5h 53m
Delta
Mon 6/110:40 pm
GEG
- MDW
1 stop9h 20m
Delta
Deal found 4/25![Delta logo]()
$335
This Alaska Airlines deal was found by Cheapflights users on 4/28. 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.
Sat 5/306:00 am
ORD
- GEG
1 stop9h 04m
Alaska Airlines
Tue 6/27:01 am
GEG
- ORD
1 stop9h 49m
Alaska Airlines
Deal found 4/28![Alaska Airlines logo]()
$336
Last-minute flights from Illinois to WashingtonDiscover last-minute flight deals from Illinois to Washington. Data last updated April 29, 2026 and is based on user searches.
Discover last-minute flight deals from Illinois to Washington. Data last updated April 29, 2026 and is based on user searches.
This Trip.com deal was found by Cheapflights users on 4/26. 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 5/79:37 pm
ORD
- SEA
1 stop14h 12m
Frontier
Mon 5/117:50 pm
SEA
- ORD
1 stop22h 42m
Frontier
Deal found 4/26![Frontier logo]()
$242
This Mytrip deal was found by Cheapflights users on 4/26. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/79:37 pm
ORD
- SEA
1 stop14h 12m
Frontier
Thu 5/147:50 pm
SEA
- ORD
1 stop22h 42m
Frontier
Deal found 4/26![Frontier logo]()
$252
This Trip.com deal was found by Cheapflights users on 4/25. 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.
Fri 5/89:37 pm
ORD
- SEA
1 stop14h 12m
Frontier
Mon 5/117:50 pm
SEA
- ORD
1 stop22h 42m
Frontier
Deal found 4/25![Frontier logo]()
$243
This Trip.com deal was found by Cheapflights users on 4/27. 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.
Fri 5/88:08 pm
STL
- SEA
1 stop15h 41m
Frontier
Fri 5/157:50 pm
SEA
- STL
1 stop21h 33m
Frontier
Deal found 4/27![Frontier logo]()
$243
This Gotogate deal was found by Cheapflights users on 4/28. 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 Gotogate is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/89:37 pm
ORD
- SEA
1 stop14h 12m
Frontier
Sun 5/107:50 pm
SEA
- ORD
1 stop22h 42m
Frontier
Deal found 4/28![Frontier logo]()
$250
This Trip.com deal was found by Cheapflights users on 4/28. 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.
Sat 5/98:08 pm
STL
- SEA
1 stop15h 41m
Frontier
Mon 5/1811:37 am
SEA
- STL
1 stop28h 29m
Frontier
Deal found 4/28![Frontier logo]()
$248
This Frontier deal was found by Cheapflights users on 4/28. 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.
Mon 5/119:37 pm
ORD
- SEA
1 stop14h 12m
Frontier
Sun 5/1711:06 am
SEA
- ORD
1 stop17h 33m
Frontier
Deal found 4/28![Frontier logo]()
$253
This Booking.com deal was found by Cheapflights users on 4/24. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 5/129:37 pm
ORD
- SEA
1 stop14h 12m
Frontier
Thu 5/147:50 pm
SEA
- ORD
1 stop22h 42m
Frontier
Deal found 4/24![Frontier logo]()
$239
This CheapOair deal was found by Cheapflights users on 4/24. 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 5/128:00 am
ORD
- SEA
Nonstop4h 40m
Alaska Airlines
Sat 5/165:42 pm
SEA
- ORD
Nonstop4h 17m
Alaska Airlines
Deal found 4/24![Alaska Airlines logo]()
$240
This Trip.com deal was found by Cheapflights users on 4/24. 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.
Tue 5/129:37 pm
ORD
- SEA
1 stop14h 12m
Frontier
Thu 5/2811:21 am
SEA
- ORD
1 stop17h 13m
Frontier
Deal found 4/24![Frontier logo]()
$244
This American Airlines deal was found by Cheapflights users on 4/24. 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.
Thu 5/1410:00 pm
ORD
- SEA
Nonstop4h 36m
American Airlines
Wed 5/203:17 pm
SEA
- ORD
Nonstop4h 23m
American Airlines
Deal found 4/24![American Airlines logo]()
$249
This Kiwi.com deal was found by Cheapflights users on 4/27. 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 5/289:37 pm
ORD
- SEA
1 stop14h 29m
Frontier
Mon 6/88:20 pm
SEA
- ORD
2 stops26h 28m
Frontier
Deal found 4/27![Frontier logo]()
$256
One-way flights from Illinois to WashingtonSearch for one-way flight options from Illinois to Washington. Find affordable one-way fares based on user searches. Data last updated April 29, 2026.
Search for one-way flight options from Illinois to Washington. Find affordable one-way fares based on user searches. Data last updated April 29, 2026.
This Kiwi.com deal was found by Cheapflights users on 4/27. 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.
Wed 5/278:08 pm
STL
- SEA
2 stops48h 27m
Frontier
Deal found 4/27![Frontier logo]()
$101
This Kiwi.com deal was found by Cheapflights users on 4/28. 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 5/268:08 pm
STL
- PDX
2 stops41h 42m
Frontier
Deal found 4/28![Frontier logo]()
$110
This Kiwi.com deal was found by Cheapflights users on 4/27. 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 5/268:08 pm
STL
- SEA
2 stops24h 27m
Frontier
Deal found 4/27![Frontier logo]()
$113
This American Airlines deal was found by Cheapflights users on 4/28. 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 6/167:04 am
STL
- SEA
1 stop9h 49m
American Airlines
Deal found 4/28![American Airlines logo]()
$125
This Kiwi.com deal was found by Cheapflights users on 4/27. 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 5/199:37 pm
ORD
- SEA
1 stop14h 12m
Frontier
Deal found 4/27![Frontier logo]()
$126
This Kiwi.com deal was found by Cheapflights users on 4/27. 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.
Wed 6/39:37 pm
ORD
- SEA
1 stop14h 29m
Frontier
Deal found 4/27![Frontier logo]()
$127
This Delta deal was found by Cheapflights users on 4/24. 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 5/167:12 am
ORD
- SEA
Nonstop4h 35m
Delta
Deal found 4/24![Delta logo]()
$128
This Kiwi.com deal was found by Cheapflights users on 4/28. 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 5/196:51 pm
STL
- SEA
2 stops25h 44m
Frontier
Deal found 4/28![Frontier logo]()
$128
This Super.com deal was found by Cheapflights users on 4/28. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 5/59:37 pm
ORD
- SEA
1 stop14h 12m
Frontier
Deal found 4/28![Frontier logo]()
$129
This Super.com deal was found by Cheapflights users on 4/28. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/79:37 pm
ORD
- SEA
1 stop14h 12m
Frontier
Deal found 4/28![Frontier logo]()
$130
This Super.com deal was found by Cheapflights users on 4/27. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/712:36 pm
STL
- SEA
1 stop23h 46m
Frontier
Deal found 4/27![Frontier logo]()
$130
This Frontier deal was found by Cheapflights users on 4/28. 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 8/289:48 pm
ORD
- SEA
1 stop14h 00m
Frontier
Deal found 4/28![Frontier logo]()
$131
Find flight deals from Illinois to Washington
Keep the following information in mind while searching for Illinois to Washington flight deals. Data was last updated April 29, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $230 (Kiwi.com) |
One-way from | $101 (Kiwi.com) |
Popular in | June |
Cheapest in | January |
Average price | $295 |
Good round-trip deal | $276 or less |
Good one-way deal | $177 or less |
Cheapflights Fare Finder
Customize your flight search to find flights from Illinois to Washington 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 April 29, 2026.
Use the filters below to find and compare flights from Illinois to Washington that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
St. LouisPortland
STL - PDX
STLPDX
Lambert-St Louis
Fri 5/29
5:33 pm-7:50 pm
Nonstop4h 17m
Portland
Wed 6/3
10:37 am-4:37 pm
Nonstop4h 00m
$283
St. LouisPortland
STL - PDX
STLPDX
Lambert-St Louis
Sat 5/30
5:33 pm-7:50 pm
Nonstop4h 17m
Portland
Tue 6/2
10:37 am-4:37 pm
Nonstop4h 00m
$289
ChicagoSpokane
ORD - GEG
ORDGEG
Chicago O'Hare Intl
Fri 5/29
2:10 pm-9:45 pm
1 stop9h 35m
Spokane
Sat 6/6
1:59 pm-10:59 pm
1 stop7h 00m
$295
ChicagoSpokane
ORD - GEG
ORDGEG
Chicago O'Hare Intl
Thu 6/4
9:00 am-9:45 pm
1 stop14h 45m
Spokane
Sat 6/6
1:59 pm-11:59 pm
1 stop8h 00m
$295
St. LouisPortland
STL - PDX
STLPDX
Lambert-St Louis
Wed 5/27
1:59 pm-10:02 pm
1 stop10h 03m
Portland
Mon 6/1
9:50 am-7:03 pm
1 stop7h 13m
$303
St. LouisSeattle
STL - SEA
STLSEA
Lambert-St Louis
Wed 7/29
7:54 pm-11:59 pm
1 stop6h 05m
Seattle/Tacoma Intl
Thu 8/6
11:59 pm-8:42 am
1 stop6h 43m
$304
St. LouisSeattle
STL - SEA
STLSEA
Lambert-St Louis
Fri 8/14
6:59 pm-12:01 am
1 stop7h 02m
Seattle/Tacoma Intl
Sat 8/22
5:45 am-1:21 pm
1 stop5h 36m
$304
St. LouisPortland
STL - PDX
STLPDX
Lambert-St Louis
Fri 5/29
7:59 pm-11:44 pm
1 stop5h 45m
Portland
Mon 6/1
11:12 pm-9:29 am
1 stop8h 17m
$309
ChicagoPortland
MDW - PDX
MDWPDX
Chicago Midway
Thu 5/28
9:50 pm-12:10 am
Nonstop4h 20m
Portland
Tue 6/2
6:10 pm-6:00 am
1 stop9h 50m
$315
Quickest round-trip
ChicagoPortland
MDW - PDX
MDWPDX
Chicago Midway
Wed 6/3
8:50 pm-11:10 pm
Nonstop4h 20m
Portland
Wed 6/10
11:30 pm-5:20 am
Nonstop3h 50m
$315
Showing 1-10 of 60 resultsSorted by cheapest first
Best time to book a flight from Illinois to Washington
Have a flexible travel schedule? Discover the best time to fly to Washington from Illinois with our price prediction graph.
ORD-SEA
STL-SEA
STL-PDX
MDW-PDX
MLI-SEA
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 Illinois to Washington
USIL-USWA
ORD-SEA
STL-SEA
STL-PDX
MDW-PDX
How far ahead should I book a flight from Illinois to State of Washington?
The price you pay for your flight from Illinois to State of Washington may vary depending on when you book. For the best chance of a lower fare, look to book 43 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.
What is the cheapest month to book a flight from Illinois to State of Washington?
Currently, May is the cheapest month in which you can book a flight from Illinois to State of Washington (average of $261). Flying from Illinois to State of Washington in January is currently the most expensive (average of $816). 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 IL to WA?
Find hourly flight availability from Illinois to Washington. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated April 29, 2026.
It’s typically best to fly out from Illinois to State of Washington in the morning. Doing so could potentially save you 11% on the flight price compared to flying in the afternoon, which is usually more expensive.
What is the cheapest day to fly from Illinois to State of Washington?
Use this chart to determine the cheapest time to fly round-trip from Illinois to Washington. Price data was last updated on April 25, 2026.
Travelers seeking maximum savings on their Illinois to State of Washington flight should consider departing on Monday evenings when fares are most often at their lowest. Sunday afternoons flights should be avoided if possible as fares are typically the most expensive at this time.
Weekly flight availability from Illinois to State of Washington
Explore weekly flight availability from Illinois to Washington. 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 April 29, 2026.
The most flights from USIL to USWA are scheduled on a Wednesday (43 on average). You will have fewer flight options on Thursday, which is when the least amount of flights are scheduled (24 on average).
How much does it cost to fly round-trip from Illinois to State of Washington?
Reviews of airlines servicing Washington
Get insights into the airlines that provide service to Washington. 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 Washington. Reviews last updated April 29, 2026.
See what other customers who have flown with Alaska Airlines,Delta, andHawaiian Airlines from Illinois to Washington have to say. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Entertainment
7.0
Food
7.1
Comfort
7.8
Boarding
8.1
Overall
7.9
Crew
8.5
Reviews
1 / 20
8.0
ExcellentEugene,Mar 2026
MFR - SEA
Entertainment
7.0
Food
7.1
Comfort
7.8
Boarding
8.1
Overall
7.9
Crew
8.5
Reviews
1 / 20
8.0
ExcellentEugene,Mar 2026
MFR - SEA
Entertainment
7.0
Food
7.1
Comfort
7.8
Boarding
8.1
Overall
7.9
Crew
8.5
Reviews
1 / 20
8.0
ExcellentEugene,Mar 2026
MFR - SEA
Entertainment
7.0
Food
7.1
Comfort
7.8
Boarding
8.1
Overall
7.9
Crew
8.5
Reviews
1 / 20
8.0
ExcellentEugene,Mar 2026
MFR - SEA
Entertainment
7.0
Food
7.1
Comfort
7.8
Boarding
8.1
Overall
7.9
Crew
8.5
Reviews
1 / 20
8.0
ExcellentEugene,Mar 2026
MFR - SEA
Entertainment
7.0
Food
7.1
Comfort
7.8
Boarding
8.1
Overall
7.9
Crew
8.5
Reviews
1 / 20
8.0
ExcellentEugene,Mar 2026
MFR - SEA
Related info for your journey
Find useful and relevant information for your journey from Illinois to Washington. 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 Illinois to Washington
See prices for flight routes from nearby airports that may be better suited for you.
Complete your trip
Complete your trip to Washington by adding a car rental and/or hotel reservation to your travel itinerary.
Search flights from Illinois to Washington by cabin class
Find flights from Illinois to Washington, based on your preferred cabin class, be it economy, premium economy, business, or first class.
Illinois and Washington flights
Browse other Illinois and Washington flight options. Last updated on April 29, 2026.
Popular flight searches
Check out other popular destinations found by fellow travelers in 2026
Find a return flight route from Washington
Find the right flight back to Illinois after your stay in Washington
Illinois to Washington flights
Consider these flights traveling from Illinois to Washington.
Top 7 airlines flying from Illinois to Washington
Discover the top 7 airlines that operate flights from Illinois to Washington. 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 April 29, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$84 | Average$229 | FlexibilityNo cancel fee | On-time85% | |
| Cheapest$110 | Average$278 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$153 | Average$258 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$168 | Average$402 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$174 | Average$443 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$177 | Average$535 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$194 | Average$358 | FlexibilityNo cancel fee | On-time63% |