$69+ Cheap flights from St. Louis (STL) 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 6/16. Fares are subject to change and may not be available on all flights or dates of travel.
STL — ORD
Jun 25 — Jul 21
Round-trip
1 adult, Economy
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Find cheap flights from St. Louis to Illinois with Cheapflights
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Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”2. Select your favorite providers
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Cheapest flights from St. Louis to IllinoisExplore the most affordable flight options available from St. Louis to Illinois. Find the lowest fares from popular airlines and budget airlines, with prices last updated on May 26, 2026.
Explore the most affordable flight options available from St. Louis to Illinois. Find the lowest fares from popular airlines and budget airlines, with prices last updated on May 26, 2026.
This Frontier deal was found by Cheapflights users on 5/24. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/117:03 pm
STL
- ORD
1 stop10h 34m
Frontier
Wed 8/125:13 pm
ORD
- STL
1 stop6h 46m
Frontier
Deal found 5/24![Frontier logo]()
$230
This American Airlines deal was found by Cheapflights users on 5/22. 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.
Tue 10/137:38 am
STL
- ORD
Nonstop1h 27m
American Airlines
Thu 10/1511:40 am
ORD
- STL
Nonstop1h 23m
American Airlines
Deal found 5/22![American Airlines logo]()
$233
This United Airlines deal was found by Cheapflights users on 5/22. 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 10/121:29 pm
STL
- ORD
Nonstop1h 31m
United Airlines
Wed 10/2112:45 pm
ORD
- STL
Nonstop1h 26m
United Airlines
Deal found 5/22![United Airlines logo]()
$234
This American Airlines deal was found by Cheapflights users on 5/21. 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 10/219:38 am
STL
- ORD
1 stop7h 58m
American Airlines
Thu 10/296:35 pm
ORD
- STL
Nonstop1h 33m
American Airlines
Deal found 5/21![American Airlines logo]()
$236
This Southwest deal was found by Cheapflights users on 5/21. 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.
Wed 7/15:40 am
STL
- MDW
Nonstop1h 05m
Southwest
Sun 7/58:05 am
MDW
- STL
Nonstop1h 25m
Southwest
Deal found 5/21![Southwest logo]()
$237
This American Airlines deal was found by Cheapflights users on 5/24. 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.
Tue 7/141:25 pm
STL
- ORD
Nonstop1h 34m
American Airlines
Sat 7/1810:59 pm
ORD
- STL
Nonstop1h 16m
American Airlines
Deal found 5/24![American Airlines logo]()
$237
This American Airlines deal was found by Cheapflights users on 5/25. 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.
Sat 8/155:23 am
STL
- ORD
1 stop5h 28m
American Airlines
Mon 8/1711:00 pm
ORD
- STL
Nonstop1h 14m
American Airlines
Deal found 5/25![American Airlines logo]()
$238
This Kiwi.com deal was found by Cheapflights users on 5/21. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 6/225:06 pm
STL
- MDW
1 stop18h 06m
Frontier
Thu 6/256:00 am
MDW
- STL
1 stop11h 30m
Frontier
Deal found 5/21![Frontier logo]()
$240
This American Airlines deal was found by Cheapflights users on 5/22. 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.
Thu 9/177:44 am
STL
- ORD
Nonstop1h 21m
American Airlines
Mon 9/216:35 pm
ORD
- STL
1 stop4h 58m
American Airlines
Deal found 5/22![American Airlines logo]()
$240
This Frontier deal was found by Cheapflights users on 5/25. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/117:03 pm
STL
- ORD
1 stop10h 34m
Frontier
Mon 8/175:13 pm
ORD
- STL
1 stop6h 46m
Frontier
Deal found 5/25![Frontier logo]()
$244
This Southwest deal was found by Cheapflights users on 5/25. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 6/153:35 pm
STL
- MDW
Nonstop1h 05m
Southwest
Wed 6/179:10 pm
MDW
- STL
Nonstop1h 15m
Southwest
Deal found 5/25![Southwest logo]()
$248
This United Airlines deal was found by Cheapflights users on 5/22. 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 6/176:00 am
STL
- ORD
Nonstop1h 30m
United Airlines
Sat 6/2010:00 pm
ORD
- STL
Nonstop1h 29m
United Airlines
Deal found 5/22![United Airlines logo]()
$248
Best flights from St. Louis to IllinoisDiscover carefully curated flight deals from St. Louis to Illinois that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated May 26, 2026.
Discover carefully curated flight deals from St. Louis to Illinois that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated May 26, 2026.
This Southwest deal was found by Cheapflights users on 5/22. 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 6/178:35 am
STL
- MDW
1 stop5h 35m
Southwest
Sat 6/206:30 am
MDW
- STL
Nonstop1h 15m
Southwest
Deal found 5/22![Southwest logo]()
$247
This Delta deal was found by Cheapflights users on 5/23. 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.
Wed 6/246:30 am
STL
- ORD
1 stop6h 34m
Delta
Fri 6/267:01 am
ORD
- STL
1 stop6h 08m
Delta
Deal found 5/23![Delta logo]()
$257
This United Airlines deal was found by Cheapflights users on 5/21. 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 7/137:05 pm
STL
- ORD
Nonstop1h 34m
United Airlines
Wed 7/157:00 am
ORD
- STL
Nonstop1h 34m
United Airlines
Deal found 5/21![United Airlines logo]()
$294
This Southwest deal was found by Cheapflights users on 5/25. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/157:50 am
STL
- MDW
2 stops5h 30m
Southwest
Mon 8/175:55 am
MDW
- STL
1 stop4h 15m
Southwest
Deal found 5/25![Southwest logo]()
$251
This KAYAK deal was found by Cheapflights users on 5/21. 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 KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/226:30 am
STL
- ORD
1 stop4h 07m
Delta
Thu 7/237:05 am
ORD
- STL
1 stop6h 00m
Delta
Deal found 5/21![Delta logo]()
$294
This United Airlines deal was found by Cheapflights users on 5/22. 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.
Tue 7/75:33 pm
STL
- ORD
Nonstop1h 31m
United Airlines
Mon 7/137:55 pm
ORD
- STL
Nonstop1h 31m
United Airlines
Deal found 5/22![United Airlines logo]()
$307
This Delta deal was found by Cheapflights users on 5/25. 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 6/176:30 am
STL
- ORD
1 stop4h 20m
Delta
Thu 6/187:01 am
ORD
- STL
1 stop6h 08m
Delta
Deal found 5/25![Delta logo]()
$297
This Southwest deal was found by Cheapflights users on 5/24. 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.
Fri 8/146:15 pm
STL
- MDW
Nonstop1h 05m
Southwest
Sun 8/167:55 am
MDW
- STL
Nonstop1h 20m
Southwest
Deal found 5/24![Southwest logo]()
$337
This United Airlines deal was found by Cheapflights users on 5/25. 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.
Sat 8/11:18 pm
STL
- ORD
Nonstop1h 30m
United Airlines
Mon 8/37:55 pm
ORD
- STL
Nonstop1h 31m
United Airlines
Deal found 5/25![United Airlines logo]()
$337
This Delta deal was found by Cheapflights users on 5/24. 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.
Tue 7/146:30 am
STL
- MDW
1 stop6h 08m
Delta
Tue 7/219:19 am
MDW
- STL
2 stops7h 27m
Delta
Deal found 5/24![Delta logo]()
$333
This United Airlines deal was found by Cheapflights users on 5/25. 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.
Fri 7/316:00 am
STL
- ORD
Nonstop1h 30m
United Airlines
Sun 8/210:40 am
ORD
- STL
Nonstop1h 31m
United Airlines
Deal found 5/25![United Airlines logo]()
$337
This Southwest deal was found by Cheapflights users on 5/22. 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.
Thu 7/212:50 pm
STL
- MDW
1 stop4h 15m
Southwest
Sun 7/129:35 pm
MDW
- STL
Nonstop1h 20m
Southwest
Deal found 5/22![Southwest logo]()
$347
This Delta deal was found by Cheapflights users on 5/25. 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 6/246:30 am
STL
- ORD
1 stop6h 34m
Delta
Wed 7/11:40 pm
ORD
- STL
2 stops9h 43m
Delta
Deal found 5/25![Delta logo]()
$333
This United Airlines deal was found by Cheapflights users on 5/26. 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 6/1011:25 am
STL
- DEC
1 stop6h 31m
United Airlines
Sun 6/146:45 pm
DEC
- STL
1 stop4h 44m
United Airlines
Deal found 5/26![United Airlines logo]()
$344
This Southwest deal was found by Cheapflights users on 5/22. 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.
Fri 7/102:15 pm
STL
- MDW
1 stop4h 50m
Southwest
Sun 7/128:05 am
MDW
- STL
Nonstop1h 25m
Southwest
Deal found 5/22![Southwest logo]()
$347
This Southwest deal was found by Cheapflights users on 5/22. 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.
Thu 8/68:30 am
STL
- MDW
1 stop6h 05m
Southwest
Sun 8/97:55 am
MDW
- STL
Nonstop1h 20m
Southwest
Deal found 5/22![Southwest logo]()
$347
This United Airlines deal was found by Cheapflights users on 5/24. 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.
Mon 6/226:00 am
STL
- ORD
Nonstop1h 30m
United Airlines
Mon 6/2910:40 am
ORD
- STL
Nonstop1h 31m
United Airlines
Deal found 5/24![United Airlines logo]()
$348
This Delta deal was found by Cheapflights users on 5/22. 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 7/288:48 am
STL
- ORD
2 stops9h 41m
Delta
Wed 7/297:05 am
ORD
- STL
1 stop6h 00m
Delta
Deal found 5/22![Delta logo]()
$362
This Southwest deal was found by Cheapflights users on 5/21. 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.
Fri 6/125:40 am
STL
- MDW
Nonstop1h 05m
Southwest
Sun 6/148:05 am
MDW
- STL
Nonstop1h 25m
Southwest
Deal found 5/21![Southwest logo]()
$359
This Delta deal was found by Cheapflights users on 5/21. 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 8/86:30 am
STL
- ORD
1 stop4h 14m
Delta
Fri 8/148:48 am
ORD
- STL
2 stops8h 04m
Delta
Deal found 5/21![Delta logo]()
$370
This United Airlines deal was found by Cheapflights users on 5/25. 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.
Sat 10/31:29 pm
STL
- DEC
1 stop4h 22m
United Airlines
Wed 10/76:55 pm
DEC
- STL
1 stop17h 18m
United Airlines
Deal found 5/25![United Airlines logo]()
$376
This Southwest deal was found by Cheapflights users on 5/25. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 6/195:40 am
STL
- MDW
Nonstop1h 05m
Southwest
Sun 6/219:35 pm
MDW
- STL
Nonstop1h 15m
Southwest
Deal found 5/25![Southwest logo]()
$369
This United Airlines deal was found by Cheapflights users on 5/21. 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.
Wed 9/301:29 pm
STL
- DEC
1 stop4h 22m
United Airlines
Sat 10/36:55 pm
DEC
- STL
1 stop4h 04m
United Airlines
Deal found 5/21![United Airlines logo]()
$379
This Delta deal was found by Cheapflights users on 5/25. 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.
Sat 8/2210:33 am
STL
- ORD
1 stop5h 44m
Delta
Thu 9/38:48 am
ORD
- STL
2 stops8h 04m
Delta
Deal found 5/25![Delta logo]()
$389
This Southwest deal was found by Cheapflights users on 5/23. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 6/205:20 am
STL
- MDW
2 stops6h 55m
Southwest
Sat 6/275:05 pm
MDW
- STL
2 stops6h 40m
Southwest
Deal found 5/23![Southwest logo]()
$388
This United Airlines deal was found by Cheapflights users on 5/21. 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.
Thu 7/91:13 pm
STL
- DEC
1 stop4h 43m
United Airlines
Fri 7/109:37 am
DEC
- STL
1 stop6h 09m
United Airlines
Deal found 5/21![United Airlines logo]()
$452
This KAYAK deal was found by Cheapflights users on 5/22. 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 KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/1011:20 am
STL
- MDW
Nonstop1h 05m
Southwest
Thu 6/119:35 pm
MDW
- STL
Nonstop1h 15m
Southwest
Deal found 5/22![Southwest logo]()
$439
This United Airlines deal was found by Cheapflights users on 5/22. 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.
Fri 6/191:13 pm
STL
- DEC
1 stop4h 43m
United Airlines
Fri 6/269:37 am
DEC
- STL
1 stop6h 09m
United Airlines
Deal found 5/22![United Airlines logo]()
$478
Last-minute flights from St. Louis to IllinoisDiscover last-minute flight deals from St. Louis to Illinois. Data last updated May 26, 2026 and is based on user searches.
Discover last-minute flight deals from St. Louis to Illinois. Data last updated May 26, 2026 and is based on user searches.
This Frontier deal was found by Cheapflights users on 5/23. 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.
Tue 6/94:17 pm
STL
- ORD
1 stop7h 02m
Frontier
Wed 6/177:20 am
ORD
- STL
1 stop11h 31m
Frontier
Deal found 5/23![Frontier logo]()
$250
This Delta deal was found by Cheapflights users on 5/22. 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 6/121:59 pm
STL
- ORD
1 stop6h 32m
Delta
Tue 6/162:07 pm
ORD
- STL
1 stop6h 32m
Delta
Deal found 5/22![Delta logo]()
$268
This Southwest deal was found by Cheapflights users on 5/25. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 6/153:35 pm
STL
- MDW
Nonstop1h 05m
Southwest
Wed 6/179:10 pm
MDW
- STL
Nonstop1h 15m
Southwest
Deal found 5/25![Southwest logo]()
$248
This American Airlines deal was found by Cheapflights users on 5/25. 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.
Mon 6/159:25 am
STL
- ORD
1 stop4h 58m
American Airlines
Wed 6/1711:00 pm
ORD
- STL
Nonstop1h 16m
American Airlines
Deal found 5/25![American Airlines logo]()
$258
This Southwest deal was found by Cheapflights users on 5/22. 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 6/179:30 pm
STL
- MDW
Nonstop1h 05m
Southwest
Sat 6/206:30 am
MDW
- STL
Nonstop1h 15m
Southwest
Deal found 5/22![Southwest logo]()
$237
This United Airlines deal was found by Cheapflights users on 5/22. 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 6/176:00 am
STL
- ORD
Nonstop1h 30m
United Airlines
Sat 6/2010:00 pm
ORD
- STL
Nonstop1h 29m
United Airlines
Deal found 5/22![United Airlines logo]()
$248
This Priceline deal was found by Cheapflights users on 5/25. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/175:06 pm
STL
- MDW
1 stop5h 05m
Frontier
Thu 6/1812:27 pm
MDW
- STL
1 stop5h 03m
Frontier
Deal found 5/25![Frontier logo]()
$249
This Kiwi.com deal was found by Cheapflights users on 5/21. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 6/225:06 pm
STL
- MDW
1 stop18h 06m
Frontier
Thu 6/256:00 am
MDW
- STL
1 stop11h 30m
Frontier
Deal found 5/21![Frontier logo]()
$240
This Frontier deal was found by Cheapflights users on 5/25. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/247:46 pm
STL
- ORD
1 stop9h 21m
Frontier
Wed 7/14:59 pm
ORD
- STL
1 stop6h 50m
Frontier
Deal found 5/25![Frontier logo]()
$230
This American Airlines deal was found by Cheapflights users on 5/25. 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.
Wed 6/248:14 pm
STL
- ORD
Nonstop1h 31m
American Airlines
Fri 6/2612:39 pm
ORD
- STL
Nonstop1h 23m
American Airlines
Deal found 5/25![American Airlines logo]()
$237
This Delta deal was found by Cheapflights users on 5/21. 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.
Wed 6/246:30 am
STL
- ORD
1 stop6h 34m
Delta
Fri 6/262:07 pm
ORD
- STL
1 stop6h 32m
Delta
Deal found 5/21![Delta logo]()
$257
This Delta deal was found by Cheapflights users on 5/21. 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.
Wed 6/246:30 am
STL
- MDW
1 stop6h 16m
Delta
Fri 6/269:17 am
MDW
- STL
1 stop3h 52m
Delta
Deal found 5/21![Delta logo]()
$268
One-way flights from St. Louis to IllinoisSearch for one-way flight options from St. Louis to Illinois. Find affordable one-way fares based on user searches. Data last updated May 26, 2026.
Search for one-way flight options from St. Louis to Illinois. Find affordable one-way fares based on user searches. Data last updated May 26, 2026.
This Southwest deal was found by Cheapflights users on 5/21. 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.
Wed 6/175:55 pm
STL
- MDW
Nonstop1h 10m
Southwest
Deal found 5/21![Southwest logo]()
$69
This American Airlines deal was found by Cheapflights users on 5/24. 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.
Tue 6/167:03 am
STL
- ORD
Nonstop1h 27m
American Airlines
Deal found 5/24![American Airlines logo]()
$69
This Delta deal was found by Cheapflights users on 5/21. 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.
Tue 6/166:30 am
STL
- MDW
1 stop6h 16m
Delta
Deal found 5/21![Delta logo]()
$79
This Delta deal was found by Cheapflights users on 5/26. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/216:30 am
STL
- ORD
1 stop6h 33m
Delta
Deal found 5/26![Delta logo]()
$79
This Southwest deal was found by Cheapflights users on 5/21. 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.
Mon 8/1711:05 am
STL
- MDW
Nonstop1h 10m
Southwest
Deal found 5/21![Southwest logo]()
$96
This American Airlines deal was found by Cheapflights users on 5/21. 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.
Mon 8/178:06 pm
STL
- ORD
Nonstop1h 34m
American Airlines
Deal found 5/21![American Airlines logo]()
$96
This Southwest deal was found by Cheapflights users on 5/25. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/1011:05 am
STL
- MDW
Nonstop1h 10m
Southwest
Deal found 5/25![Southwest logo]()
$98
This American Airlines deal was found by Cheapflights users on 5/25. 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 8/65:59 am
STL
- ORD
Nonstop1h 34m
American Airlines
Deal found 5/25![American Airlines logo]()
$98
This United Airlines deal was found by Cheapflights users on 5/21. 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.
Tue 6/166:00 am
STL
- ORD
Nonstop1h 30m
United Airlines
Deal found 5/21![United Airlines logo]()
$102
This KAYAK deal was found by Cheapflights users on 5/21. 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 KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/226:30 am
STL
- MDW
1 stop6h 08m
Delta
Deal found 5/21![Delta logo]()
$103
This KAYAK deal was found by Cheapflights users on 5/21. 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 KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/226:30 am
STL
- ORD
1 stop6h 33m
Delta
Deal found 5/21![Delta logo]()
$103
This United Airlines deal was found by Cheapflights users on 5/26. 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.
Tue 7/217:05 pm
STL
- ORD
Nonstop1h 34m
United Airlines
Deal found 5/26![United Airlines logo]()
$104
Find flight deals from St. Louis to Illinois
Keep the following information in mind while searching for St. Louis to Illinois flight deals. Data was last updated May 26, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $230 (Frontier) |
One-way from | $69 (Southwest) |
Popular in | January |
Cheapest in | August |
Average price | $338 |
Good round-trip deal | $365 or less |
Good one-way deal | $199 or less |
Cheapflights Fare Finder
Customize your flight search to find flights from St. Louis 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 May 26, 2026.
Use the filters below to find and compare flights from St. Louis to Illinois that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
St. LouisChicago
STL - MDW
STLMDW
Lambert-St Louis
Wed 6/17
8:35 am-2:10 pm
1 stop5h 35m
Chicago Midway
Sat 6/20
6:30 am-7:45 am
Nonstop1h 15m
$247
St. LouisChicago
STL - MDW
STLMDW
Lambert-St Louis
Sat 8/15
7:50 am-1:20 pm
2 stops5h 30m
Chicago Midway
Mon 8/17
5:55 am-10:10 am
1 stop4h 15m
$251
St. LouisChicago
STL - ORD
STLORD
Lambert-St Louis
Wed 6/24
6:30 am-1:04 pm
1 stop6h 34m
Chicago O'Hare Intl
Fri 6/26
7:01 am-1:09 pm
1 stop6h 08m
$257
St. LouisChicago
STL - ORD
STLORD
Lambert-St Louis
Mon 7/13
7:05 pm-8:39 pm
Nonstop1h 34m
Chicago O'Hare Intl
Wed 7/15
7:00 am-8:34 am
Nonstop1h 34m
$294
St. LouisChicago
STL - ORD
STLORD
Lambert-St Louis
Wed 7/22
6:30 am-10:37 am
1 stop4h 07m
Chicago O'Hare Intl
Thu 7/23
7:05 am-1:05 pm
1 stop6h 00m
$294
St. LouisChicago
STL - ORD
STLORD
Lambert-St Louis
Wed 6/17
6:30 am-10:50 am
1 stop4h 20m
Chicago O'Hare Intl
Thu 6/18
7:01 am-1:09 pm
1 stop6h 08m
$297
St. LouisChicago
STL - ORD
STLORD
Lambert-St Louis
Tue 7/7
5:33 pm-7:04 pm
Nonstop1h 31m
Chicago O'Hare Intl
Mon 7/13
7:55 pm-9:26 pm
Nonstop1h 31m
$307
St. LouisChicago
STL - MDW
STLMDW
Lambert-St Louis
Tue 7/14
6:30 am-12:38 pm
1 stop6h 08m
Chicago Midway
Tue 7/21
9:19 am-4:46 pm
2 stops7h 27m
$333
St. LouisChicago
STL - ORD
STLORD
Lambert-St Louis
Wed 6/24
6:30 am-1:04 pm
1 stop6h 34m
Chicago O'Hare Intl
Wed 7/1
1:40 pm-11:23 pm
2 stops9h 43m
$333
St. LouisChicago
STL - MDW
STLMDW
Lambert-St Louis
Fri 8/14
6:15 pm-7:20 pm
Nonstop1h 05m
Chicago Midway
Sun 8/16
7:55 am-9:15 am
Nonstop1h 20m
$337
Showing 1-10 of 49 resultsSorted by cheapest first
Best time to book a flight from St. Louis to Illinois
Have a flexible travel schedule? Discover the best time to fly to Illinois from St. Louis with our price prediction graph.
STL-ORD
STL-MDW
STL-DEC
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 St. Louis to Illinois
STL-USIL
STL-ORD
STL-MDW
STL-DEC
What is the cheapest month to book a flight from St. Louis to Illinois?
Currently, August is the cheapest month in which you can book a flight from St. Louis to Illinois (average of $61). Flying from St. Louis to Illinois in February is currently the most expensive (average of $117). 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 STL to IL?
Find hourly flight availability from St. Louis 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 May 26, 2026.
When flying from St. Louis to Illinois, the time of day you fly usually plays a role in the price. Save by searching for a flight in the morning, which can drop the price by up to 30% versus a flight at noon.
Weekly flight availability from St. Louis to Illinois
Explore weekly flight availability from St. Louis 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 May 26, 2026.
The most flights from STL to USIL are scheduled on a Monday (82 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (41 on average).
How much does it cost to fly round-trip from St. Louis to Illinois?
How far ahead should I book a flight from St. Louis to Illinois?
The best time to book flights from St. Louis to Illinois is 72 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 St. Louis to Illinois?
Use this chart to determine the cheapest time to fly round-trip from St. Louis to Illinois. Price data was last updated on May 23, 2026.
Travelers seeking maximum savings on their St. Louis to Illinois flight should consider departing on Wednesday evenings when fares are most often at their lowest. Monday 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 May 26, 2026.
See what other customers who have flown with Southwest,United Airlines, andAmerican Airlines from St. Louis to Illinois have to say. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
Food
7.0
Comfort
8.0
Crew
8.6
Boarding
8.1
Overall
7.9
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Food
7.0
Comfort
8.0
Crew
8.6
Boarding
8.1
Overall
7.9
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Food
7.0
Comfort
8.0
Crew
8.6
Boarding
8.1
Overall
7.9
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Food
7.0
Comfort
8.0
Crew
8.6
Boarding
8.1
Overall
7.9
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Food
7.0
Comfort
8.0
Crew
8.6
Boarding
8.1
Overall
7.9
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Related info for your journey
Find useful and relevant information for your journey from St. Louis 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 St. Louis to Illinois
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Complete your trip
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St. Louis and Illinois flights
Browse other St. Louis and Illinois flight options. Last updated on May 26, 2026.
Popular flight searches
Check out other popular destinations found by fellow travelers in 2026
St. Louis to Illinois flights
Consider these flights traveling from St. Louis to Illinois.
Top 3 airlines flying from St. Louis to Illinois
Discover the top 3 airlines that operate flights from St. Louis 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 May 26, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$97 | Average$313 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$117 | Average$461 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$117 | Average$364 | FlexibilityNo cancel fee | On-time69% |