$49+ 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 8/20. Fares are subject to change and may not be available on all flights or dates of travel.
STL — ORD
Aug 20 — Aug 271
Round-trip
1 adult, Economy
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Find cheap flights from St. Louis to Illinois with Cheapflights
1. Tell us where you want to go
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 July 21, 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 July 21, 2026.
This United Airlines deal was found by Cheapflights users on 7/21. 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 12/107:04 pm
STL
- ORD
Nonstop1h 27m
United Airlines
Wed 1/137:45 pm
ORD
- STL
Nonstop1h 28m
United Airlines
Deal found 7/21![United Airlines logo]()
$167
This United Airlines deal was found by Cheapflights users on 7/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/58:00 am
STL
- ORD
Nonstop1h 34m
United Airlines
Sun 9/68:40 am
ORD
- STL
Nonstop1h 32m
United Airlines
Deal found 7/20![United Airlines logo]()
$177
This Kiwi.com deal was found by Cheapflights users on 7/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/174:57 pm
STL
- ORD
1 stop14h 56m
Frontier
Mon 8/247:05 am
ORD
- STL
1 stop10h 17m
Frontier
Deal found 7/20![Frontier logo]()
$182
This Delta deal was found by Cheapflights users on 7/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/162:18 pm
STL
- ORD
1 stop4h 22m
Delta
Mon 11/237:05 am
ORD
- STL
1 stop6h 15m
Delta
Deal found 7/20![Delta logo]()
$186
This American Airlines deal was found by Cheapflights users on 7/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/248:07 pm
STL
- ORD
Nonstop1h 33m
American Airlines
Thu 8/2711:00 pm
ORD
- STL
Nonstop1h 14m
American Airlines
Deal found 7/20![American Airlines logo]()
$194
This Southwest deal was found by Cheapflights users on 7/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/155:45 am
STL
- MDW
Nonstop1h 05m
Southwest
Sat 8/226:15 pm
MDW
- STL
Nonstop1h 15m
Southwest
Deal found 7/18![Southwest logo]()
$195
This United Airlines deal was found by Cheapflights users on 7/17. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/108:00 am
STL
- ORD
Nonstop1h 35m
United Airlines
Wed 8/127:05 am
ORD
- STL
Nonstop1h 34m
United Airlines
Deal found 7/17![United Airlines logo]()
$195
This American Airlines deal was found by Cheapflights users on 7/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/128:07 pm
STL
- ORD
Nonstop1h 33m
American Airlines
Thu 8/1311:00 pm
ORD
- STL
Nonstop1h 14m
American Airlines
Deal found 7/18![American Airlines logo]()
$196
This Kiwi.com deal was found by Cheapflights users on 7/16. Clicking the “Pick Dates” 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 8/236:17 pm
STL
- ORD
1 stop13h 36m
Frontier
Wed 8/261:59 pm
ORD
- STL
1 stop27h 23m
Frontier
Deal found 7/16![Frontier logo]()
$197
This Kiwi.com deal was found by Cheapflights users on 7/17. Clicking the “Pick Dates” 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 8/104:57 pm
STL
- ORD
1 stop15h 05m
Frontier
Tue 8/111:50 pm
ORD
- STL
1 stop19h 07m
Frontier
Deal found 7/17![Frontier logo]()
$201
This Kiwi.com deal was found by Cheapflights users on 7/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/2210:35 am
STL
- ORD
1 stop9h 53m
Frontier
Mon 10/264:49 pm
ORD
- STL
2 stops40h 51m
Frontier
Deal found 7/19![Frontier logo]()
$202
This Southwest deal was found by Cheapflights users on 7/17. Clicking the “Pick Dates” 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 10/273:35 pm
STL
- MDW
2 stops6h 40m
Southwest
Wed 10/288:05 am
MDW
- STL
Nonstop1h 10m
Southwest
Deal found 7/17![Southwest logo]()
$206
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 July 21, 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 July 21, 2026.
This Southwest deal was found by Cheapflights users on 7/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/1910:45 am
STL
- MDW
Nonstop1h 05m
Southwest
Sat 8/226:35 am
MDW
- STL
Nonstop1h 10m
Southwest
Deal found 7/19![Southwest logo]()
$195
This United Airlines deal was found by Cheapflights users on 7/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/179:30 am
STL
- ORD
Nonstop1h 30m
United Airlines
Mon 8/247:05 am
ORD
- STL
Nonstop1h 34m
United Airlines
Deal found 7/18![United Airlines logo]()
$195
This Delta deal was found by Cheapflights users on 7/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/106:45 am
STL
- ORD
1 stop5h 52m
Delta
Wed 1/131:35 pm
ORD
- STL
1 stop7h 02m
Delta
Deal found 7/18![Delta logo]()
$215
This Southwest deal was found by Cheapflights users on 7/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/172:20 pm
STL
- MDW
Nonstop1h 05m
Southwest
Mon 8/249:20 am
MDW
- STL
Nonstop1h 10m
Southwest
Deal found 7/18![Southwest logo]()
$195
This United Airlines deal was found by Cheapflights users on 7/17. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/108:00 am
STL
- ORD
Nonstop1h 35m
United Airlines
Wed 8/127:05 am
ORD
- STL
Nonstop1h 34m
United Airlines
Deal found 7/17![United Airlines logo]()
$195
This Southwest deal was found by Cheapflights users on 7/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/242:20 pm
STL
- MDW
Nonstop1h 05m
Southwest
Thu 8/279:20 am
MDW
- STL
Nonstop1h 10m
Southwest
Deal found 7/20![Southwest logo]()
$195
This United Airlines deal was found by Cheapflights users on 7/17. Clicking the “Pick Dates” 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 9/178:00 am
STL
- ORD
Nonstop1h 34m
United Airlines
Thu 9/172:07 pm
ORD
- STL
Nonstop1h 31m
United Airlines
Deal found 7/17![United Airlines logo]()
$195
This Delta deal was found by Cheapflights users on 7/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/242:10 pm
STL
- ORD
1 stop4h 19m
Delta
Thu 8/2711:22 am
ORD
- STL
1 stop6h 16m
Delta
Deal found 7/20![Delta logo]()
$215
This Southwest deal was found by Cheapflights users on 7/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/253:45 pm
STL
- MDW
Nonstop1h 05m
Southwest
Thu 8/273:10 pm
MDW
- STL
Nonstop1h 10m
Southwest
Deal found 7/18![Southwest logo]()
$195
This United Airlines deal was found by Cheapflights users on 7/17. Clicking the “Pick Dates” 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 9/811:15 am
STL
- ORD
Nonstop1h 36m
United Airlines
Wed 9/96:30 pm
ORD
- STL
Nonstop1h 31m
United Airlines
Deal found 7/17![United Airlines logo]()
$195
This Delta deal was found by Cheapflights users on 7/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/1810:33 am
STL
- ORD
1 stop5h 44m
Delta
Tue 8/2511:22 am
ORD
- STL
1 stop6h 16m
Delta
Deal found 7/18![Delta logo]()
$215
This Southwest deal was found by Cheapflights users on 7/17. Clicking the “Pick Dates” 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 8/102:20 pm
STL
- MDW
Nonstop1h 05m
Southwest
Wed 8/122:00 pm
MDW
- STL
Nonstop1h 10m
Southwest
Deal found 7/17![Southwest logo]()
$195
This Delta deal was found by Cheapflights users on 7/17. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/86:40 am
STL
- ORD
1 stop6h 19m
Delta
Wed 9/91:55 pm
ORD
- STL
1 stop6h 40m
Delta
Deal found 7/17![Delta logo]()
$215
This Delta deal was found by Cheapflights users on 7/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/810:33 am
STL
- ORD
1 stop5h 44m
Delta
Sat 8/152:30 pm
ORD
- STL
1 stop6h 12m
Delta
Deal found 7/18![Delta logo]()
$215
This United Airlines deal was found by Cheapflights users on 7/21. 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 11/238:33 am
STL
- ORD
Nonstop1h 31m
United Airlines
Fri 11/274:35 pm
ORD
- STL
Nonstop1h 31m
United Airlines
Deal found 7/21![United Airlines logo]()
$217
This Southwest deal was found by Cheapflights users on 7/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/158:30 am
STL
- MDW
1 stop5h 20m
Southwest
Sat 8/226:35 am
MDW
- STL
Nonstop1h 10m
Southwest
Deal found 7/18![Southwest logo]()
$205
This Delta deal was found by Cheapflights users on 7/21. 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 12/126:45 am
STL
- ORD
1 stop3h 48m
Delta
Thu 1/71:35 pm
ORD
- STL
1 stop7h 02m
Delta
Deal found 7/21![Delta logo]()
$225
This Southwest deal was found by Cheapflights users on 7/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/187:15 am
STL
- MDW
1 stop6h 15m
Southwest
Tue 8/258:15 am
MDW
- STL
Nonstop1h 20m
Southwest
Deal found 7/18![Southwest logo]()
$205
This United Airlines deal was found by Cheapflights users on 7/16. Clicking the “Pick Dates” 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 8/66:00 am
STL
- ORD
Nonstop1h 30m
United Airlines
Mon 8/1010:00 pm
ORD
- STL
Nonstop1h 29m
United Airlines
Deal found 7/16![United Airlines logo]()
$227
This Southwest deal was found by Cheapflights users on 7/17. Clicking the “Pick Dates” 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 9/2210:55 am
STL
- MDW
1 stop5h 10m
Southwest
Wed 10/288:50 pm
MDW
- STL
Nonstop1h 10m
Southwest
Deal found 7/17![Southwest logo]()
$205
This Southwest deal was found by Cheapflights users on 7/17. Clicking the “Pick Dates” 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 9/88:25 am
STL
- MDW
1 stop4h 35m
Southwest
Wed 9/93:05 pm
MDW
- STL
1 stop6h 05m
Southwest
Deal found 7/17![Southwest logo]()
$215
This Southwest deal was found by Cheapflights users on 7/21. 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.
Thu 8/208:50 pm
STL
- MDW
Nonstop1h 05m
Southwest
Sun 8/237:55 am
MDW
- STL
Nonstop1h 20m
Southwest
Deal found 7/21![Southwest logo]()
$217
This Southwest deal was found by Cheapflights users on 7/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/25:25 am
STL
- MDW
Nonstop1h 05m
Southwest
Tue 10/68:05 am
MDW
- STL
Nonstop1h 10m
Southwest
Deal found 7/20![Southwest logo]()
$217
This United Airlines deal was found by Cheapflights users on 7/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/41:13 pm
STL
- DEC
1 stop4h 43m
United Airlines
Sat 8/86:45 pm
DEC
- STL
1 stop4h 44m
United Airlines
Deal found 7/20![United Airlines logo]()
$341
This United Airlines deal was found by Cheapflights users on 7/17. Clicking the “Pick Dates” 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 8/1512:59 pm
STL
- DEC
1 stop5h 00m
United Airlines
Fri 8/217:20 pm
DEC
- STL
1 stop3h 39m
United Airlines
Deal found 7/17![United Airlines logo]()
$344
This United Airlines deal was found by Cheapflights users on 7/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/1712:59 pm
STL
- DEC
1 stop5h 00m
United Airlines
Mon 8/247:20 pm
DEC
- STL
1 stop16h 42m
United Airlines
Deal found 7/19![United Airlines logo]()
$378
Last-minute flights from St. Louis to IllinoisDiscover last-minute flight deals from St. Louis to Illinois. Data last updated July 21, 2026 and is based on user searches.
Discover last-minute flight deals from St. Louis to Illinois. Data last updated July 21, 2026 and is based on user searches.
This United Airlines deal was found by Cheapflights users on 7/16. Clicking the “Pick Dates” 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 8/66:00 am
STL
- ORD
Nonstop1h 30m
United Airlines
Thu 8/67:55 pm
ORD
- STL
Nonstop1h 31m
United Airlines
Deal found 7/16![United Airlines logo]()
$187
This United Airlines deal was found by Cheapflights users on 7/17. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/108:00 am
STL
- ORD
Nonstop1h 35m
United Airlines
Wed 8/127:05 am
ORD
- STL
Nonstop1h 34m
United Airlines
Deal found 7/17![United Airlines logo]()
$195
This Kiwi.com deal was found by Cheapflights users on 7/17. Clicking the “Pick Dates” 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 8/104:57 pm
STL
- ORD
1 stop15h 05m
Frontier
Tue 8/111:50 pm
ORD
- STL
1 stop19h 07m
Frontier
Deal found 7/17![Frontier logo]()
$201
This American Airlines deal was found by Cheapflights users on 7/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/128:07 pm
STL
- ORD
Nonstop1h 33m
American Airlines
Thu 8/1311:00 pm
ORD
- STL
Nonstop1h 14m
American Airlines
Deal found 7/18![American Airlines logo]()
$196
This Delta deal was found by Cheapflights users on 7/21. 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.
Thu 8/136:30 am
STL
- ORD
1 stop4h 12m
Delta
Mon 8/171:41 pm
ORD
- STL
1 stop7h 01m
Delta
Deal found 7/21![Delta logo]()
$167
This United Airlines deal was found by Cheapflights users on 7/21. 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 8/137:25 am
STL
- ORD
Nonstop1h 36m
United Airlines
Mon 8/178:29 pm
ORD
- STL
Nonstop1h 31m
United Airlines
Deal found 7/21![United Airlines logo]()
$168
This Southwest deal was found by Cheapflights users on 7/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/155:45 am
STL
- MDW
Nonstop1h 05m
Southwest
Sat 8/226:15 pm
MDW
- STL
Nonstop1h 15m
Southwest
Deal found 7/18![Southwest logo]()
$195
This Kiwi.com deal was found by Cheapflights users on 7/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/174:57 pm
STL
- ORD
1 stop14h 56m
Frontier
Mon 8/247:05 am
ORD
- STL
1 stop10h 17m
Frontier
Deal found 7/20![Frontier logo]()
$182
This Southwest deal was found by Cheapflights users on 7/17. Clicking the “Pick Dates” 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 8/183:45 pm
STL
- MDW
Nonstop1h 05m
Southwest
Sat 8/2210:05 am
MDW
- STL
2 stops6h 45m
Southwest
Deal found 7/17![Southwest logo]()
$210
This Kiwi.com deal was found by Cheapflights users on 7/16. Clicking the “Pick Dates” 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 8/216:17 pm
STL
- ORD
1 stop13h 36m
Frontier
Sun 8/237:05 am
ORD
- STL
1 stop10h 17m
Frontier
Deal found 7/16![Frontier logo]()
$204
This Kiwi.com deal was found by Cheapflights users on 7/16. Clicking the “Pick Dates” 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 8/236:17 pm
STL
- ORD
1 stop13h 36m
Frontier
Wed 8/261:59 pm
ORD
- STL
1 stop27h 23m
Frontier
Deal found 7/16![Frontier logo]()
$197
This American Airlines deal was found by Cheapflights users on 7/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/248:07 pm
STL
- ORD
Nonstop1h 33m
American Airlines
Thu 8/2711:00 pm
ORD
- STL
Nonstop1h 14m
American Airlines
Deal found 7/20![American Airlines logo]()
$194
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 July 21, 2026.
Search for one-way flight options from St. Louis to Illinois. Find affordable one-way fares based on user searches. Data last updated July 21, 2026.
This Southwest deal was found by Cheapflights users on 7/21. 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.
Thu 8/208:50 pm
STL
- MDW
Nonstop1h 05m
Southwest
Deal found 7/21![Southwest logo]()
$49
This United Airlines deal was found by Cheapflights users on 7/21. 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 8/209:30 am
STL
- ORD
Nonstop1h 30m
United Airlines
Deal found 7/21![United Airlines logo]()
$49
This United Airlines deal was found by Cheapflights users on 7/16. Clicking the “Pick Dates” 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 8/158:00 am
STL
- ORD
Nonstop1h 34m
United Airlines
Deal found 7/16![United Airlines logo]()
$59
This Kiwi.com deal was found by Cheapflights users on 7/17. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/116:34 pm
STL
- ORD
1 stop13h 28m
Frontier
Deal found 7/17![Frontier logo]()
$63
This Southwest deal was found by Cheapflights users on 7/16. Clicking the “Pick Dates” 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 8/1510:15 am
STL
- MDW
1 stop6h 25m
Southwest
Deal found 7/16![Southwest logo]()
$69
This Kiwi.com deal was found by Cheapflights users on 7/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/1610:35 am
STL
- ORD
1 stop25h 27m
Frontier
Deal found 7/19![Frontier logo]()
$73
This Delta deal was found by Cheapflights users on 7/16. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/176:30 am
STL
- MDW
1 stop6h 09m
Delta
Deal found 7/16![Delta logo]()
$79
This Delta deal was found by Cheapflights users on 7/16. Clicking the “Pick Dates” 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 8/1510:33 am
STL
- ORD
1 stop5h 44m
Delta
Deal found 7/16![Delta logo]()
$79
This United Airlines deal was found by Cheapflights users on 7/21. 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 10/195:36 pm
STL
- ORD
Nonstop1h 29m
United Airlines
Deal found 7/21![United Airlines logo]()
$84
This Kiwi.com deal was found by Cheapflights users on 7/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/1210:35 am
STL
- ORD
1 stop25h 27m
Frontier
Deal found 7/20![Frontier logo]()
$91
This Southwest deal was found by Cheapflights users on 7/16. Clicking the “Pick Dates” 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 8/138:50 pm
STL
- MDW
Nonstop1h 05m
Southwest
Deal found 7/16![Southwest logo]()
$94
This United Airlines deal was found by Cheapflights users on 7/16. Clicking the “Pick Dates” 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 8/139:30 am
STL
- ORD
Nonstop1h 30m
United Airlines
Deal found 7/16![United Airlines logo]()
$94
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 July 21, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $177 (United Airlines) |
One-way from | $49 (Southwest) |
Popular in | January |
Cheapest in | August |
Average price | $361 |
Good round-trip deal | $332 or less |
Good one-way deal | $198 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 July 21, 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
Quickest round-trip
St. LouisChicago
STL - MDW
STLMDW
Lambert-St Louis
Wed 8/19
10:45 am-11:50 am
Nonstop1h 05m
Chicago Midway
Sat 8/22
6:35 am-7:45 am
Nonstop1h 10m
$195
St. LouisChicago
STL - ORD
STLORD
Lambert-St Louis
Mon 8/17
9:30 am-11:00 am
Nonstop1h 30m
Chicago O'Hare Intl
Mon 8/24
7:05 am-8:39 am
Nonstop1h 34m
$195
St. LouisChicago
STL - MDW
STLMDW
Lambert-St Louis
Mon 8/17
2:20 pm-3:25 pm
Nonstop1h 05m
Chicago Midway
Mon 8/24
9:20 am-10:30 am
Nonstop1h 10m
$195
St. LouisChicago
STL - ORD
STLORD
Lambert-St Louis
Mon 8/10
8:00 am-9:35 am
Nonstop1h 35m
Chicago O'Hare Intl
Wed 8/12
7:05 am-8:39 am
Nonstop1h 34m
$195
St. LouisChicago
STL - MDW
STLMDW
Lambert-St Louis
Mon 8/24
2:20 pm-3:25 pm
Nonstop1h 05m
Chicago Midway
Thu 8/27
9:20 am-10:30 am
Nonstop1h 10m
$195
St. LouisChicago
STL - ORD
STLORD
Lambert-St Louis
Thu 9/17
8:00 am-9:34 am
Nonstop1h 34m
Chicago O'Hare Intl
Thu 9/17
2:07 pm-3:38 pm
Nonstop1h 31m
$195
St. LouisChicago
STL - MDW
STLMDW
Lambert-St Louis
Tue 8/25
3:45 pm-4:50 pm
Nonstop1h 05m
Chicago Midway
Thu 8/27
3:10 pm-4:20 pm
Nonstop1h 10m
$195
St. LouisChicago
STL - ORD
STLORD
Lambert-St Louis
Tue 9/8
11:15 am-12:51 pm
Nonstop1h 36m
Chicago O'Hare Intl
Wed 9/9
6:30 pm-8:01 pm
Nonstop1h 31m
$195
St. LouisChicago
STL - MDW
STLMDW
Lambert-St Louis
Mon 8/10
2:20 pm-3:25 pm
Nonstop1h 05m
Chicago Midway
Wed 8/12
2:00 pm-3:10 pm
Nonstop1h 10m
$195
St. LouisChicago
STL - MDW
STLMDW
Lambert-St Louis
Sat 8/15
8:30 am-1:50 pm
1 stop5h 20m
Chicago Midway
Sat 8/22
6:35 am-7:45 am
Nonstop1h 10m
$205
Showing 1-10 of 48 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
STL-UIN
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
STL-UIN
What is the cheapest month to book a flight from St. Louis to Illinois?
Currently, October is the cheapest month in which you can book a flight from St. Louis to Illinois (average of $269). Flying from St. Louis to Illinois in February is currently the most expensive (average of $440). 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 July 21, 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 31% 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 July 21, 2026.
The most flights from STL to USIL are scheduled on a Monday (75 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (35 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 70 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 July 18, 2026.
Travelers seeking maximum savings on their St. Louis to Illinois flight should consider departing on Tuesday at noon when fares are most often at their lowest. Tuesday 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 July 21, 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.
Overall
8.0
Crew
8.6
Comfort
8.0
Boarding
8.1
Entertainment
7.5
Food
7.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Overall
8.0
Crew
8.6
Comfort
8.0
Boarding
8.1
Entertainment
7.5
Food
7.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Overall
8.0
Crew
8.6
Comfort
8.0
Boarding
8.1
Entertainment
7.5
Food
7.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Overall
8.0
Crew
8.6
Comfort
8.0
Boarding
8.1
Entertainment
7.5
Food
7.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Overall
8.0
Crew
8.6
Comfort
8.0
Boarding
8.1
Entertainment
7.5
Food
7.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
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
Complete your trip to Illinois by adding a car rental and/or hotel reservation to your travel itinerary.
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Find flights from St. Louis to Illinois, based on your preferred cabin class, be it economy, premium economy, business, or first class.
St. Louis and Illinois flights
Browse other St. Louis and Illinois flight options. Last updated on July 21, 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 July 21, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$97 | Average$317 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$145 | Average$415 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$165 | Average$490 | FlexibilityNo cancel fee | On-time63% |