$117+ Cheap flights from Oregon 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 10/17. Fares are subject to change and may not be available on all flights or dates of travel.
PDX — ORD
Aug 29 — Sep 51
Round-trip
1 adult, Economy
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Find cheap flights from Oregon to Illinois with Cheapflights
1. Tell us where you want to go
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Cheapest flights from Oregon to IllinoisExplore the most affordable flight options available from Oregon to Illinois. Find the lowest fares from popular airlines and budget airlines, with prices last updated on July 30, 2026.
Explore the most affordable flight options available from Oregon to Illinois. Find the lowest fares from popular airlines and budget airlines, with prices last updated on July 30, 2026.
This Kiwi.com deal was found by Cheapflights users on 7/29. 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 9/25:56 pm
PDX
- STL
1 stop23h 17m
Frontier
Wed 9/98:10 pm
STL
- PDX
1 stop17h 33m
Frontier
Deal found 7/29![Frontier logo]()
$234
This CheapOair deal was found by Cheapflights users on 7/30. 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 9/1112:39 pm
PDX
- STL
1 stop20h 53m
Frontier
Sun 9/131:02 pm
STL
- PDX
1 stop24h 41m
Frontier
Deal found 7/30![Frontier logo]()
$240
This Kiwi.com deal was found by Cheapflights users on 7/27. 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 8/265:56 pm
PDX
- STL
1 stop23h 17m
Frontier
Mon 8/317:58 pm
STL
- PDX
1 stop23h 13m
Frontier
Deal found 7/27![Frontier logo]()
$242
This Frontier deal was found by Cheapflights users on 7/29. 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.
Thu 8/2012:24 pm
BOI
- ORD
1 stop24h 12m
Frontier
Wed 8/262:41 pm
ORD
- BOI
1 stop21h 48m
Frontier
Deal found 7/29![Frontier logo]()
$253
This CheapOair deal was found by Cheapflights users on 7/29. 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 9/142:50 pm
BOI
- ORD
1 stop13h 48m
Frontier
Wed 9/161:21 pm
ORD
- BOI
1 stop25h 34m
Frontier
Deal found 7/29![Frontier logo]()
$259
This CheapOair deal was found by Cheapflights users on 7/27. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/89:34 pm
PDX
- STL
1 stop25h 43m
Frontier
Sun 10/115:19 pm
STL
- PDX
1 stop29h 20m
Frontier
Deal found 7/27![Frontier logo]()
$265
This Frontier deal was found by Cheapflights users on 7/30. 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 10/93:52 pm
BOI
- ORD
1 stop12h 50m
Frontier
Mon 10/126:50 am
ORD
- BOI
1 stop9h 07m
Frontier
Deal found 7/30![Frontier logo]()
$267
This CheapOair deal was found by Cheapflights users on 7/28. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/271:47 pm
PDX
- STL
1 stop26h 03m
Frontier
Thu 9/36:45 pm
STL
- PDX
1 stop24h 36m
Frontier
Deal found 7/28![Frontier logo]()
$268
This Frontier deal was found by Cheapflights users on 7/27. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/163:52 pm
BOI
- ORD
1 stop12h 50m
Frontier
Sun 11/17:00 am
ORD
- BOI
1 stop8h 57m
Frontier
Deal found 7/27![Frontier logo]()
$269
This Kiwi.com deal was found by Cheapflights users on 7/30. 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 9/1312:38 pm
PDX
- STL
2 stops25h 56m
Frontier
Sun 9/208:10 pm
STL
- PDX
1 stop17h 33m
Frontier
Deal found 7/30![Frontier logo]()
$273
This CheapOair deal was found by Cheapflights users on 7/27. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/112:50 pm
BOI
- ORD
1 stop13h 48m
Frontier
Sun 9/138:55 pm
ORD
- BOI
1 stop18h 00m
Frontier
Deal found 7/27![Frontier logo]()
$274
This Kiwi.com deal was found by Cheapflights users on 7/29. 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 9/1012:38 pm
PDX
- STL
2 stops22h 32m
Frontier
Sun 9/131:02 pm
STL
- PDX
1 stop24h 41m
Frontier
Deal found 7/29![Frontier logo]()
$275
Best flights from Oregon to IllinoisDiscover carefully curated flight deals from Oregon to Illinois that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated July 30, 2026.
Discover carefully curated flight deals from Oregon to Illinois that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated July 30, 2026.
This United Airlines deal was found by Cheapflights users on 7/29. 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 10/2812:37 pm
BOI
- ORD
Nonstop3h 33m
United Airlines
Sat 10/317:45 pm
ORD
- BOI
Nonstop4h 06m
United Airlines
Deal found 7/29![United Airlines logo]()
$313
This Alaska Airlines deal was found by Cheapflights users on 7/28. 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 10/166:04 pm
BOI
- ORD
1 stop10h 36m
Alaska Airlines
Mon 10/196:00 am
ORD
- BOI
1 stop7h 35m
Alaska Airlines
Deal found 7/28![Alaska Airlines logo]()
$322
This American Airlines deal was found by Cheapflights users on 7/25. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/111:08 pm
PDX
- STL
1 stop9h 12m
American Airlines
Mon 10/511:31 am
STL
- PDX
1 stop10h 10m
American Airlines
Deal found 7/25![American Airlines logo]()
$329
This Delta deal was found by Cheapflights users on 7/29. 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 10/15:20 am
EUG
- STL
1 stop6h 10m
Delta
Wed 10/72:38 pm
STL
- EUG
2 stops11h 21m
Delta
Deal found 7/29![Delta logo]()
$331
This Southwest deal was found by Cheapflights users on 7/29. 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 10/2811:55 am
BOI
- MDW
1 stop7h 25m
Southwest
Sat 10/315:30 am
MDW
- BOI
1 stop5h 35m
Southwest
Deal found 7/29![Southwest logo]()
$333
This Kiwi.com deal was found by Cheapflights users on 7/25. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/201:05 pm
MFR
- ORD
2 stops30h 34m
Multiple Airlines
Sun 9/278:55 pm
ORD
- MFR
1 stop19h 55m
Multiple Airlines
Deal found 7/25![Multiple Airlines logo]()
$424
This United Airlines deal was found by Cheapflights users on 7/29. 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 9/145:40 pm
BOI
- ORD
1 stop5h 19m
United Airlines
Wed 9/168:40 am
ORD
- BOI
Nonstop3h 46m
United Airlines
Deal found 7/29![United Airlines logo]()
$323
This Delta deal was found by Cheapflights users on 7/27. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/1211:35 pm
BOI
- MDW
1 stop9h 58m
Delta
Mon 11/165:25 pm
MDW
- BOI
1 stop7h 31m
Delta
Deal found 7/27![Delta logo]()
$333
This Southwest deal was found by Cheapflights users on 7/29. 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 10/2811:55 am
BOI
- MDW
2 stops8h 05m
Southwest
Thu 10/295:40 am
MDW
- BOI
1 stop6h 40m
Southwest
Deal found 7/29![Southwest logo]()
$334
This Alaska Airlines deal was found by Cheapflights users on 7/29. 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 10/317:00 am
EUG
- ORD
1 stop9h 53m
Alaska Airlines
Tue 11/32:25 pm
ORD
- EUG
1 stop26h 13m
Alaska Airlines
Deal found 7/29![Alaska Airlines logo]()
$343
This Southwest deal was found by Cheapflights users on 7/29. 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 8/2012:40 pm
PDX
- STL
1 stop9h 10m
Southwest
Fri 8/216:05 am
STL
- PDX
2 stops10h 55m
Southwest
Deal found 7/29![Southwest logo]()
$334
This Delta deal was found by Cheapflights users on 7/28. 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 9/21:59 pm
BOI
- MDW
1 stop7h 37m
Delta
Sun 9/66:05 am
MDW
- BOI
1 stop7h 44m
Delta
Deal found 7/28![Delta logo]()
$335
This United Airlines deal was found by Cheapflights users on 7/27. 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.
Thu 9/242:15 pm
EUG
- ORD
Nonstop4h 11m
United Airlines
Wed 9/309:05 am
ORD
- EUG
Nonstop4h 45m
United Airlines
Deal found 7/27![United Airlines logo]()
$339
This Alaska Airlines deal was found by Cheapflights users on 7/28. 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.
Tue 10/277:00 am
EUG
- ORD
1 stop9h 53m
Alaska Airlines
Wed 10/282:21 pm
ORD
- EUG
1 stop8h 00m
Alaska Airlines
Deal found 7/28![Alaska Airlines logo]()
$343
This Southwest deal was found by Cheapflights users on 7/27. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/267:05 am
BOI
- MDW
2 stops9h 05m
Southwest
Thu 8/274:55 pm
MDW
- BOI
1 stop8h 00m
Southwest
Deal found 7/27![Southwest logo]()
$338
This Delta deal was found by Cheapflights users on 7/28. 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 9/91:06 pm
BOI
- ORD
1 stop7h 49m
Delta
Sat 9/197:45 am
ORD
- BOI
2 stops11h 55m
Delta
Deal found 7/28![Delta logo]()
$338
This United Airlines deal was found by Cheapflights users on 7/30. 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 9/92:19 pm
EUG
- ORD
Nonstop4h 11m
United Airlines
Mon 9/1410:25 am
ORD
- EUG
Nonstop4h 45m
United Airlines
Deal found 7/30![United Airlines logo]()
$339
This Alaska Airlines deal was found by Cheapflights users on 7/30. 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 9/97:08 am
EUG
- ORD
1 stop10h 13m
Alaska Airlines
Sun 9/138:17 pm
ORD
- EUG
1 stop18h 24m
Alaska Airlines
Deal found 7/30![Alaska Airlines logo]()
$351
This Delta deal was found by Cheapflights users on 7/25. 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 9/108:55 am
BOI
- ORD
1 stop8h 06m
Delta
Mon 9/142:05 pm
ORD
- BOI
2 stops10h 53m
Delta
Deal found 7/25![Delta logo]()
$338
This Southwest deal was found by Cheapflights users on 7/29. 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 9/112:35 pm
BOI
- MDW
2 stops8h 45m
Southwest
Fri 9/115:40 am
MDW
- BOI
1 stop6h 50m
Southwest
Deal found 7/29![Southwest logo]()
$340
This United Airlines deal was found by Cheapflights users on 7/26. 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.
Wed 9/237:15 am
EUG
- STL
1 stop9h 24m
United Airlines
Sat 9/264:49 pm
STL
- EUG
1 stop6h 23m
United Airlines
Deal found 7/26![United Airlines logo]()
$349
This Alaska Airlines deal was found by Cheapflights users on 7/26. 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.
Wed 8/128:00 pm
BOI
- ORD
1 stop16h 21m
Alaska Airlines
Wed 8/196:00 am
ORD
- BOI
1 stop9h 22m
Alaska Airlines
Deal found 7/26![Alaska Airlines logo]()
$353
This Delta deal was found by Cheapflights users on 7/27. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/63:36 pm
BOI
- ORD
1 stop6h 58m
Delta
Sat 10/3110:55 am
ORD
- BOI
2 stops10h 41m
Delta
Deal found 7/27![Delta logo]()
$338
This United Airlines deal was found by Cheapflights users on 7/25. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/312:47 pm
EUG
- STL
1 stop8h 44m
United Airlines
Sat 9/54:40 pm
STL
- EUG
1 stop6h 42m
United Airlines
Deal found 7/25![United Airlines logo]()
$349
This Alaska Airlines deal was found by Cheapflights users on 7/29. 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 10/207:00 am
EUG
- ORD
1 stop28h 25m
Alaska Airlines
Sat 10/247:20 am
ORD
- EUG
1 stop9h 12m
Alaska Airlines
Deal found 7/29![Alaska Airlines logo]()
$353
This Southwest deal was found by Cheapflights users on 7/26. 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.
Thu 9/31:15 pm
EUG
- STL
1 stop7h 30m
Southwest
Tue 9/82:45 pm
STL
- EUG
2 stops9h 50m
Southwest
Deal found 7/26![Southwest logo]()
$354
This Delta deal was found by Cheapflights users on 7/27. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/221:06 pm
BOI
- ORD
1 stop7h 27m
Delta
Wed 9/26:00 am
ORD
- BOI
2 stops12h 19m
Delta
Deal found 7/27![Delta logo]()
$338
This United Airlines deal was found by Cheapflights users on 7/26. 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 9/182:19 pm
EUG
- ORD
Nonstop4h 11m
United Airlines
Sat 9/262:30 pm
ORD
- EUG
1 stop8h 42m
United Airlines
Deal found 7/26![United Airlines logo]()
$349
This Southwest deal was found by Cheapflights users on 7/28. 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 8/2911:30 pm
PDX
- MDW
Nonstop3h 55m
Southwest
Sat 9/126:00 pm
MDW
- PDX
Nonstop4h 20m
Southwest
Deal found 7/28![Southwest logo]()
$357
This Alaska Airlines deal was found by Cheapflights users on 7/27. 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.
Thu 12/106:00 am
BOI
- ORD
1 stop6h 09m
Alaska Airlines
Sun 12/135:55 pm
ORD
- BOI
1 stop7h 16m
Alaska Airlines
Deal found 7/27![Alaska Airlines logo]()
$359
Last-minute flights from Oregon to IllinoisDiscover last-minute flight deals from Oregon to Illinois. Data last updated July 30, 2026 and is based on user searches.
Discover last-minute flight deals from Oregon to Illinois. Data last updated July 30, 2026 and is based on user searches.
This CheapOair deal was found by Cheapflights users on 7/28. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/115:16 pm
PDX
- STL
1 stop24h 07m
Frontier
Sun 8/167:10 pm
STL
- PDX
1 stop23h 44m
Frontier
Deal found 7/28![Frontier logo]()
$298
This CheapOair deal was found by Cheapflights users on 7/27. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/111:24 pm
BOI
- ORD
1 stop6h 28m
Frontier
Sat 8/159:57 pm
ORD
- BOI
1 stop15h 32m
Frontier
Deal found 7/27![Frontier logo]()
$304
This CheapOair deal was found by Cheapflights users on 7/28. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/136:49 pm
PDX
- STL
1 stop21h 26m
Frontier
Sun 8/167:10 pm
STL
- PDX
1 stop23h 44m
Frontier
Deal found 7/28![Frontier logo]()
$278
This CheapOair deal was found by Cheapflights users on 7/26. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/195:56 pm
PDX
- STL
1 stop23h 17m
Frontier
Mon 8/247:58 pm
STL
- PDX
1 stop23h 13m
Frontier
Deal found 7/26![Frontier logo]()
$251
This Frontier deal was found by Cheapflights users on 7/29. 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.
Thu 8/2012:24 pm
BOI
- ORD
1 stop24h 12m
Frontier
Wed 8/262:41 pm
ORD
- BOI
1 stop21h 48m
Frontier
Deal found 7/29![Frontier logo]()
$253
This CheapOair deal was found by Cheapflights users on 7/30. 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 8/2012:24 pm
BOI
- ORD
1 stop24h 12m
Frontier
Mon 8/242:41 pm
ORD
- BOI
1 stop22h 48m
Frontier
Deal found 7/30![Frontier logo]()
$267
This CheapOair deal was found by Cheapflights users on 7/27. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/246:17 pm
PDX
- STL
1 stop21h 33m
Frontier
Mon 8/317:58 pm
STL
- PDX
1 stop23h 13m
Frontier
Deal found 7/27![Frontier logo]()
$258
This Kiwi.com deal was found by Cheapflights users on 7/27. 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 8/265:56 pm
PDX
- STL
1 stop23h 17m
Frontier
Mon 8/317:58 pm
STL
- PDX
1 stop23h 13m
Frontier
Deal found 7/27![Frontier logo]()
$242
This Priceline deal was found by Cheapflights users on 7/27. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/2611:16 am
PDX
- STL
Nonstop3h 54m
Alaska Airlines
Wed 9/26:08 pm
STL
- PDX
Nonstop4h 12m
Alaska Airlines
Deal found 7/27![Alaska Airlines logo]()
$297
This Gotogate deal was found by Cheapflights users on 7/27. 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 Gotogate is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/267:20 am
BOI
- ORD
1 stop11h 01m
Alaska Airlines
Wed 9/26:00 am
ORD
- BOI
1 stop7h 36m
Alaska Airlines
Deal found 7/27![Alaska Airlines logo]()
$309
This CheapOair deal was found by Cheapflights users on 7/28. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/271:47 pm
PDX
- STL
1 stop26h 03m
Frontier
Thu 9/36:45 pm
STL
- PDX
1 stop24h 36m
Frontier
Deal found 7/28![Frontier logo]()
$268
This Southwest deal was found by Cheapflights users on 7/30. 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 8/299:00 am
PDX
- STL
1 stop7h 25m
Southwest
Sat 9/58:30 am
STL
- PDX
Nonstop4h 10m
Southwest
Deal found 7/30![Southwest logo]()
$307
One-way flights from Oregon to IllinoisSearch for one-way flight options from Oregon to Illinois. Find affordable one-way fares based on user searches. Data last updated July 30, 2026.
Search for one-way flight options from Oregon to Illinois. Find affordable one-way fares based on user searches. Data last updated July 30, 2026.
This Alaska Airlines deal was found by Cheapflights users on 7/30. 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 10/1710:30 am
PDX
- STL
2 stops11h 29m
Alaska Airlines
Deal found 7/30![Alaska Airlines logo]()
$117
This Kiwi.com deal was found by Cheapflights users on 7/28. 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.
Fri 9/2512:38 pm
PDX
- STL
1 stop28h 39m
Frontier
Deal found 7/28![Frontier logo]()
$119
This Frontier deal was found by Cheapflights users on 7/29. 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 10/263:52 pm
BOI
- ORD
1 stop12h 50m
Frontier
Deal found 7/29![Frontier logo]()
$122
This Kiwi.com deal was found by Cheapflights users on 7/28. 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.
Thu 9/1712:38 pm
PDX
- STL
1 stop28h 39m
Frontier
Deal found 7/28![Frontier logo]()
$123
This Kiwi.com deal was found by Cheapflights users on 7/26. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/265:56 pm
PDX
- STL
1 stop23h 17m
Frontier
Deal found 7/26![Frontier logo]()
$124
This Kiwi.com deal was found by Cheapflights users on 7/30. 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 9/11:24 pm
BOI
- ORD
1 stop23h 12m
Frontier
Deal found 7/30![Frontier logo]()
$127
This Trip.com deal was found by Cheapflights users on 7/27. 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.
Thu 8/2712:20 pm
PDX
- STL
1 stop28h 53m
Frontier
Deal found 7/27![Frontier logo]()
$129
This Frontier deal was found by Cheapflights users on 7/27. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/293:52 pm
BOI
- ORD
1 stop12h 43m
Frontier
Deal found 7/27![Frontier logo]()
$132
This CheapOair deal was found by Cheapflights users on 7/28. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/286:17 pm
PDX
- STL
1 stop21h 33m
Frontier
Deal found 7/28![Frontier logo]()
$135
This CheapOair deal was found by Cheapflights users on 7/29. 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 9/282:50 pm
BOI
- ORD
1 stop13h 48m
Frontier
Deal found 7/29![Frontier logo]()
$137
This CheapOair deal was found by Cheapflights users on 7/26. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/252:50 pm
BOI
- ORD
1 stop13h 48m
Frontier
Deal found 7/26![Frontier logo]()
$138
This Kiwi.com deal was found by Cheapflights users on 7/29. 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 9/272:50 pm
BOI
- ORD
1 stop13h 48m
Frontier
Deal found 7/29![Frontier logo]()
$141
Find flight deals from Oregon to Illinois
Keep the following information in mind while searching for Oregon to Illinois flight deals. Data was last updated July 30, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $234 (Kiwi.com) |
One-way from | $117 (Alaska Airlines) |
Popular in | November |
Cheapest in | January |
Average price | $372 |
Good round-trip deal | $355 or less |
Good one-way deal | $208 or less |
Cheapflights Fare Finder
Customize your flight search to find flights from Oregon 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 July 30, 2026.
Use the filters below to find and compare flights from Oregon to Illinois that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
Quickest round-trip
BoiseChicago
BOI - ORD
BOIORD
Boise Air Term. Gowen Fld
Wed 10/28
12:37 pm-5:10 pm
Nonstop3h 33m
Chicago O'Hare Intl
Sat 10/31
7:45 pm-10:51 pm
Nonstop4h 06m
$313
BoiseChicago
BOI - ORD
BOIORD
Boise Air Term. Gowen Fld
Fri 10/16
6:04 pm-5:40 am
1 stop10h 36m
Chicago O'Hare Intl
Mon 10/19
6:00 am-12:35 pm
1 stop7h 35m
$322
BoiseChicago
BOI - ORD
BOIORD
Boise Air Term. Gowen Fld
Mon 9/14
5:40 pm-11:59 pm
1 stop5h 19m
Chicago O'Hare Intl
Wed 9/16
8:40 am-11:26 am
Nonstop3h 46m
$323
PortlandSt. Louis
PDX - STL
PDXSTL
Portland
Thu 10/1
11:08 pm-10:20 am
1 stop9h 12m
Lambert-St Louis
Mon 10/5
11:31 am-7:41 pm
1 stop10h 10m
$329
EugeneSt. Louis
EUG - STL
EUGSTL
Eugene
Thu 10/1
5:20 am-1:30 pm
1 stop6h 10m
Lambert-St Louis
Wed 10/7
2:38 pm-11:59 pm
2 stops11h 21m
$331
BoiseChicago
BOI - MDW
BOIMDW
Boise Air Term. Gowen Fld
Wed 10/28
11:55 am-8:20 pm
1 stop7h 25m
Chicago Midway
Sat 10/31
5:30 am-10:05 am
1 stop5h 35m
$333
BoiseChicago
BOI - MDW
BOIMDW
Boise Air Term. Gowen Fld
Thu 11/12
11:35 pm-10:33 am
1 stop9h 58m
Chicago Midway
Mon 11/16
5:25 pm-11:56 pm
1 stop7h 31m
$333
BoiseChicago
BOI - MDW
BOIMDW
Boise Air Term. Gowen Fld
Wed 10/28
11:55 am-9:00 pm
2 stops8h 05m
Chicago Midway
Thu 10/29
5:40 am-11:20 am
1 stop6h 40m
$334
PortlandSt. Louis
PDX - STL
PDXSTL
Portland
Thu 8/20
12:40 pm-11:50 pm
1 stop9h 10m
Lambert-St Louis
Fri 8/21
6:05 am-3:00 pm
2 stops10h 55m
$334
BoiseChicago
BOI - MDW
BOIMDW
Boise Air Term. Gowen Fld
Wed 9/2
1:59 pm-10:36 pm
1 stop7h 37m
Chicago Midway
Sun 9/6
6:05 am-12:49 pm
1 stop7h 44m
$335
Showing 1-10 of 60 resultsSorted by cheapest first
Best time to book a flight from Oregon to Illinois
Have a flexible travel schedule? Discover the best time to fly to Illinois from Oregon with our price prediction graph.
PDX-STL
BOI-ORD
BOI-MDW
RDM-ORD
EUG-STL
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 Oregon to Illinois
USOR-USIL
PDX-STL
BOI-ORD
BOI-MDW
RDM-ORD
What is the cheapest month to book a flight from Oregon to Illinois?
Currently, January is the cheapest month in which you can book a flight from Oregon to Illinois (average of $295). Flying from Oregon to Illinois in June is currently the most expensive (average of $416). 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 OR to IL?
Find hourly flight availability from Oregon 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 July 30, 2026.
It’s optimal to fly from Oregon to Illinois in the afternoon. By choosing this option you can save up to 33% on the cost of your flight, compared to a flight at noon.
Weekly flight availability from Oregon to Illinois
Explore weekly flight availability from Oregon 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 July 30, 2026.
The most flights from USOR to USIL are scheduled on a Tuesday (34 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (17 on average).
How much does it cost to fly round-trip from Oregon to Illinois?
Airfare is typical for this route at the moment.
Oregon to Illinois flights typically cost between $315 and $441 in September.The cheapest round-trip price found within the last 5 days was $319 on Frontier (Sep 3-Sep 10).
How far ahead should I book a flight from Oregon to Illinois?
The best time to book flights from Oregon to Illinois is 29 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.
What is the cheapest day to fly from Oregon to Illinois?
Use this chart to determine the cheapest time to fly round-trip from Oregon to Illinois. Price data was last updated on July 25, 2026.
Travelers seeking maximum savings on their Oregon to Illinois flight should consider departing on Saturday at noon 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.
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 July 30, 2026.
Peruse reviews from past customers who have flown with Southwest,Alaska Airlines, andDelta from Oregon to Illinois to help guide your decision. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Food
7.0
Crew
8.6
Overall
8.0
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Food
7.0
Crew
8.6
Overall
8.0
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Food
7.0
Crew
8.6
Overall
8.0
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Food
7.0
Crew
8.6
Overall
8.0
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Food
7.0
Crew
8.6
Overall
8.0
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Food
7.0
Crew
8.6
Overall
8.0
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Related info for your journey
Find useful and relevant information for your journey from Oregon to Illinois. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
Browse thousands of different options on Cheapflights for your next trip
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Alternative routes for Oregon 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 Oregon to Illinois by cabin class
Find flights from Oregon to Illinois, based on your preferred cabin class, be it economy, premium economy, business, or first class.
Oregon and Illinois flights
Browse other Oregon and Illinois flight options. Last updated on July 30, 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 Oregon after your stay in Illinois
Oregon to Illinois flights
Consider these flights traveling from Oregon to Illinois.
Top 7 airlines flying from Oregon to Illinois
Discover the top 7 airlines that operate flights from Oregon 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 July 30, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$86 | Average$238 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$93 | Average$217 | FlexibilityNo cancel fee | On-time85% | |
| Cheapest$108 | Average$394 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$195 | Average$467 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$198 | Average$424 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$227 | Average$356 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$228 | Average$459 | FlexibilityNo cancel fee | On-time69% |