$59+ 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 9/22. Fares are subject to change and may not be available on all flights or dates of travel.
STL — ORD
Sep 24 — Oct 11
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 August 25, 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 August 25, 2026.
This Southwest deal was found by Cheapflights users on 8/25. 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.
Thu 9/178:50 pm -
Nonstop1h 10m
Thu 9/249:20 am -
Nonstop1h 10m
Deal found 8/25![Southwest logo]()
$117
This United Airlines deal was found by Cheapflights users on 8/21. 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 10/16:00 am -
Nonstop1h 36m
Mon 10/57:50 pm -
Nonstop1h 31m
Deal found 8/21![United Airlines logo]()
$117
This Priceline deal was found by Cheapflights users on 8/21. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/212:29 pm -
1 stop9h 15m
Wed 9/236:25 am -
1 stop6h 45m
Deal found 8/21![Frontier logo]()
$118
This American Airlines deal was found by Cheapflights users on 8/23. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/177:27 am -
Nonstop1h 38m
Mon 9/213:17 pm -
Nonstop1h 31m
Deal found 8/23![American Airlines logo]()
$118
This Frontier deal was found by Cheapflights users on 8/22. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/212:29 pm -
1 stop9h 15m
Mon 9/286:25 am -
1 stop6h 45m
Deal found 8/22![Frontier logo]()
$119
This American Airlines deal was found by Cheapflights users on 8/20. 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.
Thu 9/105:00 am -
Nonstop1h 29m
Mon 9/1411:05 pm -
Nonstop1h 22m
Deal found 8/20![American Airlines logo]()
$119
This Frontier deal was found by Cheapflights users on 8/20. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/1010:20 am -
1 stop9h 15m
Mon 9/148:55 pm -
1 stop14h 37m
Deal found 8/20![Frontier logo]()
$120
This Super.com deal was found by Cheapflights users on 8/25. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/288:10 pm -
1 stop28h 13m
Wed 9/306:20 am -
1 stop6h 50m
Deal found 8/25![Frontier logo]()
$124
This Super.com deal was found by Cheapflights users on 8/20. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/308:10 pm -
1 stop28h 13m
Wed 10/76:20 am -
1 stop6h 50m
Deal found 8/20![Frontier logo]()
$125
This Southwest deal was found by Cheapflights users on 8/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/128:25 am -
Nonstop1h 05m
Sat 9/121:20 pm -
1 stop6h 35m
Deal found 8/21![Southwest logo]()
$127
This CheapOair deal was found by Cheapflights users on 8/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/224:30 pm -
1 stop15h 01m
Mon 10/266:20 am -
1 stop10h 38m
Deal found 8/23![Frontier logo]()
$128
This Trip.com deal was found by Cheapflights users on 8/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/148:10 pm -
1 stop28h 13m
Wed 9/166:20 am -
1 stop6h 50m
Deal found 8/23![Frontier logo]()
$130
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 August 25, 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 August 25, 2026.
This United Airlines deal was found by Cheapflights users on 8/24. 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 9/218:00 am -
Nonstop1h 34m
Mon 9/287:50 pm -
Nonstop1h 31m
Deal found 8/24![United Airlines logo]()
$117
This Southwest deal was found by Cheapflights users on 8/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/173:00 pm -
1 stop4h 40m
Mon 10/1910:05 pm -
Nonstop1h 10m
Deal found 8/21![Southwest logo]()
$127
This Delta deal was found by Cheapflights users on 8/23. 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 10/76:47 am -
1 stop3h 42m
Wed 10/141:55 pm -
1 stop6h 56m
Deal found 8/23![Delta logo]()
$157
This United Airlines deal was found by Cheapflights users on 8/22. 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 10/125:36 pm -
Nonstop1h 29m
Tue 10/137:50 pm -
Nonstop1h 31m
Deal found 8/22![United Airlines logo]()
$117
This Southwest deal was found by Cheapflights users on 8/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/1412:15 pm -
Nonstop1h 10m
Tue 11/174:25 pm -
1 stop6h 00m
Deal found 8/21![Southwest logo]()
$127
This Southwest deal was found by Cheapflights users on 8/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/34:40 pm -
Nonstop1h 05m
Sat 10/108:00 am -
1 stop5h 00m
Deal found 8/22![Southwest logo]()
$127
This Delta deal was found by Cheapflights users on 8/22. 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.
Mon 10/122:38 pm -
1 stop3h 51m
Tue 10/138:29 am -
1 stop5h 24m
Deal found 8/22![Delta logo]()
$157
This Southwest deal was found by Cheapflights users on 8/23. 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.
Wed 10/710:20 am -
1 stop4h 00m
Wed 10/144:45 pm -
1 stop5h 40m
Deal found 8/23![Southwest logo]()
$137
This Delta deal was found by Cheapflights users on 8/21. 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 12/102:18 pm -
1 stop6h 07m
Wed 1/131:35 pm -
1 stop7h 02m
Deal found 8/21![Delta logo]()
$157
This Delta deal was found by Cheapflights users on 8/22. 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.
Thu 12/36:32 am -
1 stop4h 27m
Sat 12/59:59 am -
1 stop4h 45m
Deal found 8/22![Delta logo]()
$157
This Southwest deal was found by Cheapflights users on 8/24. 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 9/182:25 pm -
1 stop4h 30m
Mon 9/218:55 pm -
Nonstop1h 15m
Deal found 8/24![Southwest logo]()
$144
This Southwest deal was found by Cheapflights users on 8/24. 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 10/210:00 pm -
Nonstop1h 05m
Tue 10/61:05 pm -
2 stops5h 55m
Deal found 8/24![Southwest logo]()
$149
This United Airlines deal was found by Cheapflights users on 8/24. 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.
Thu 10/18:00 am -
Nonstop1h 31m
Sun 10/410:40 am -
Nonstop1h 35m
Deal found 8/24![United Airlines logo]()
$232
This Southwest deal was found by Cheapflights users on 8/22. 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 10/305:25 am -
Nonstop1h 05m
Fri 10/304:15 pm -
1 stop4h 40m
Deal found 8/22![Southwest logo]()
$161
This United Airlines deal was found by Cheapflights users on 8/22. 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 10/167:01 pm -
Nonstop1h 29m
Sun 10/187:50 pm -
Nonstop1h 31m
Deal found 8/22![United Airlines logo]()
$249
This United Airlines deal was found by Cheapflights users on 8/20. 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.
Wed 9/912:59 pm -
Nonstop1h 31m
Thu 9/1010:25 am -
Nonstop1h 32m
Deal found 8/20![United Airlines logo]()
$251
This Delta deal was found by Cheapflights users on 8/20. 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.
Thu 11/122:18 pm -
1 stop6h 07m
Sun 11/158:29 am -
1 stop4h 54m
Deal found 8/20![Delta logo]()
$262
This United Airlines deal was found by Cheapflights users on 8/24. 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.
Sat 9/128:30 am -
Nonstop1h 35m
Wed 9/1610:25 am -
Nonstop1h 32m
Deal found 8/24![United Airlines logo]()
$251
This Southwest deal was found by Cheapflights users on 8/20. 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 12/46:20 am -
Nonstop1h 05m
Fri 12/45:20 pm -
1 stop4h 35m
Deal found 8/20![Southwest logo]()
$210
This United Airlines deal was found by Cheapflights users on 8/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/208:00 am -
Nonstop1h 34m
Fri 9/259:30 pm -
Nonstop1h 29m
Deal found 8/22![United Airlines logo]()
$260
This Southwest deal was found by Cheapflights users on 8/24. 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.
Thu 10/110:00 pm -
Nonstop1h 05m
Sun 10/48:15 am -
Nonstop1h 10m
Deal found 8/24![Southwest logo]()
$232
This Southwest deal was found by Cheapflights users on 8/23. 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.
Fri 9/258:50 pm -
Nonstop1h 10m
Sun 9/278:25 pm -
Nonstop1h 15m
Deal found 8/23![Southwest logo]()
$249
This United Airlines deal was found by Cheapflights users on 8/20. 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 10/316:00 am -
1 stop27h 35m
Wed 11/49:10 am -
1 stop12h 25m
Deal found 8/20![United Airlines logo]()
$334
This Expedia deal was found by Cheapflights users on 8/23. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/177:36 pm -
2 stops18h 19m
Mon 9/219:55 am -
2 stops14h 04m
Deal found 8/23![Multiple Airlines logo]()
$1,198
This United Airlines deal was found by Cheapflights users on 8/24. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/1812:59 pm -
1 stop5h 45m
Sun 9/207:20 pm -
1 stop3h 39m
Deal found 8/24![United Airlines logo]()
$483
This United Airlines deal was found by Cheapflights users on 8/23. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/712:59 pm -
1 stop5h 00m
Fri 9/117:20 pm -
1 stop3h 39m
Deal found 8/23![United Airlines logo]()
$612
Last-minute flights from St. Louis to IllinoisDiscover last-minute flight deals from St. Louis to Illinois. Data last updated August 25, 2026 and is based on user searches.
Discover last-minute flight deals from St. Louis to Illinois. Data last updated August 25, 2026 and is based on user searches.
This American Airlines deal was found by Cheapflights users on 8/20. 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.
Thu 9/105:00 am -
Nonstop1h 29m
Mon 9/1411:05 pm -
Nonstop1h 22m
Deal found 8/20![American Airlines logo]()
$119
This Frontier deal was found by Cheapflights users on 8/20. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/1010:20 am -
1 stop9h 15m
Mon 9/148:55 pm -
1 stop14h 37m
Deal found 8/20![Frontier logo]()
$120
This Southwest deal was found by Cheapflights users on 8/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/128:25 am -
Nonstop1h 05m
Sat 9/121:20 pm -
1 stop6h 35m
Deal found 8/21![Southwest logo]()
$127
This Southwest deal was found by Cheapflights users on 8/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/126:45 am -
2 stops6h 20m
Mon 9/148:55 pm -
Nonstop1h 15m
Deal found 8/21![Southwest logo]()
$132
This Trip.com deal was found by Cheapflights users on 8/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/148:10 pm -
1 stop28h 13m
Wed 9/166:20 am -
1 stop6h 50m
Deal found 8/23![Frontier logo]()
$130
This Southwest deal was found by Cheapflights users on 8/25. 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.
Thu 9/178:50 pm -
Nonstop1h 10m
Thu 9/249:20 am -
Nonstop1h 10m
Deal found 8/25![Southwest logo]()
$117
This American Airlines deal was found by Cheapflights users on 8/24. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/175:00 am -
Nonstop1h 29m
Thu 9/2411:05 pm -
Nonstop1h 22m
Deal found 8/24![American Airlines logo]()
$118
This United Airlines deal was found by Cheapflights users on 8/24. 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 9/218:00 am -
Nonstop1h 34m
Mon 9/287:50 pm -
Nonstop1h 31m
Deal found 8/24![United Airlines logo]()
$117
This Priceline deal was found by Cheapflights users on 8/21. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/212:29 pm -
1 stop9h 15m
Wed 9/236:25 am -
1 stop6h 45m
Deal found 8/21![Frontier logo]()
$118
This Frontier deal was found by Cheapflights users on 8/22. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/212:29 pm -
1 stop9h 15m
Mon 9/286:25 am -
1 stop6h 45m
Deal found 8/22![Frontier logo]()
$119
This Super.com deal was found by Cheapflights users on 8/25. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/288:10 pm -
1 stop28h 13m
Wed 9/306:20 am -
1 stop6h 50m
Deal found 8/25![Frontier logo]()
$124
This Super.com deal was found by Cheapflights users on 8/20. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/308:10 pm -
1 stop28h 13m
Wed 10/76:20 am -
1 stop6h 50m
Deal found 8/20![Frontier logo]()
$125
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 August 25, 2026.
Search for one-way flight options from St. Louis to Illinois. Find affordable one-way fares based on user searches. Data last updated August 25, 2026.
This Southwest deal was found by Cheapflights users on 8/21. 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 10/214:05 pm -
Nonstop1h 05m
Deal found 8/21![Southwest logo]()
$59
This United Airlines deal was found by Cheapflights users on 8/24. 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.
Thu 10/16:00 am -
Nonstop1h 36m
Deal found 8/24![United Airlines logo]()
$59
This American Airlines deal was found by Cheapflights users on 8/25. 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 10/125:00 am -
Nonstop1h 26m
Deal found 8/25![American Airlines logo]()
$60
This Super.com deal was found by Cheapflights users on 8/25. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/282:29 pm -
1 stop9h 15m
Deal found 8/25![Frontier logo]()
$64
This Super.com deal was found by Cheapflights users on 8/20. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/1010:20 am -
1 stop9h 15m
Deal found 8/20![Frontier logo]()
$64
This Frontier deal was found by Cheapflights users on 8/25. 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.
Mon 9/212:29 pm -
1 stop9h 15m
Deal found 8/25![Frontier logo]()
$65
This Frontier deal was found by Cheapflights users on 8/25. 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.
Thu 10/110:20 am -
1 stop9h 15m
Deal found 8/25![Frontier logo]()
$65
This Trip.com deal was found by Cheapflights users on 8/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/142:29 pm -
1 stop9h 15m
Deal found 8/20![Frontier logo]()
$66
This CheapOair deal was found by Cheapflights users on 8/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/238:10 pm -
1 stop28h 13m
Deal found 8/21![Frontier logo]()
$66
This Trip.com deal was found by Cheapflights users on 8/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/148:10 pm -
1 stop28h 13m
Deal found 8/20![Frontier logo]()
$67
This Trip.com deal was found by Cheapflights users on 8/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/58:10 pm -
1 stop28h 13m
Deal found 8/21![Frontier logo]()
$68
This Southwest deal was found by Cheapflights users on 8/25. 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.
Wed 10/73:35 pm -
2 stops6h 40m
Deal found 8/25![Southwest logo]()
$69
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 August 25, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $117 (Southwest) |
One-way from | $59 (Southwest) |
Popular in | January |
Cheapest in | August |
Average price | $257 |
Good round-trip deal | $300 or less |
Good one-way deal | $196 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 7,457,451 searches. Data last updated August 25, 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 Lambert-St Louis - ORD Chicago O'Hare Intl
STLORD
Lambert-St Louis
Mon 9/21
8:00 am-9:34 am
Nonstop1h 34m
Chicago O'Hare Intl
Mon 9/28
7:50 pm-9:21 pm
Nonstop1h 31m
$117
St. LouisChicago
STL Lambert-St Louis - ORD Chicago O'Hare Intl
STLORD
Lambert-St Louis
Mon 10/12
5:36 pm-7:05 pm
Nonstop1h 29m
Chicago O'Hare Intl
Tue 10/13
7:50 pm-9:21 pm
Nonstop1h 31m
$117
St. LouisChicago
STL Lambert-St Louis - MDW Chicago Midway
STLMDW
Lambert-St Louis
Sat 10/17
3:00 pm-7:40 pm
1 stop4h 40m
Chicago Midway
Mon 10/19
10:05 pm-11:15 pm
Nonstop1h 10m
$127
St. LouisChicago
STL Lambert-St Louis - MDW Chicago Midway
STLMDW
Lambert-St Louis
Sat 11/14
12:15 pm-1:25 pm
Nonstop1h 10m
Chicago Midway
Tue 11/17
4:25 pm-10:25 pm
1 stop6h 00m
$127
St. LouisChicago
STL Lambert-St Louis - MDW Chicago Midway
STLMDW
Lambert-St Louis
Sat 10/3
4:40 pm-5:45 pm
Nonstop1h 05m
Chicago Midway
Sat 10/10
8:00 am-1:00 pm
1 stop5h 00m
$127
St. LouisChicago
STL Lambert-St Louis - MDW Chicago Midway
STLMDW
Lambert-St Louis
Wed 10/7
10:20 am-2:20 pm
1 stop4h 00m
Chicago Midway
Wed 10/14
4:45 pm-10:25 pm
1 stop5h 40m
$137
St. LouisChicago
STL Lambert-St Louis - MDW Chicago Midway
STLMDW
Lambert-St Louis
Fri 9/18
2:25 pm-6:55 pm
1 stop4h 30m
Chicago Midway
Mon 9/21
8:55 pm-10:10 pm
Nonstop1h 15m
$144
St. LouisChicago
STL Lambert-St Louis - MDW Chicago Midway
STLMDW
Lambert-St Louis
Fri 10/2
10:00 pm-11:05 pm
Nonstop1h 05m
Chicago Midway
Tue 10/6
1:05 pm-7:00 pm
2 stops5h 55m
$149
St. LouisChicago
STL Lambert-St Louis - ORD Chicago O'Hare Intl
STLORD
Lambert-St Louis
Wed 10/7
6:47 am-10:29 am
1 stop3h 42m
Chicago O'Hare Intl
Wed 10/14
1:55 pm-8:51 pm
1 stop6h 56m
$157
St. LouisChicago
STL Lambert-St Louis - ORD Chicago O'Hare Intl
STLORD
Lambert-St Louis
Mon 10/12
2:38 pm-6:29 pm
1 stop3h 51m
Chicago O'Hare Intl
Tue 10/13
8:29 am-1:53 pm
1 stop5h 24m
$157
Showing 1-10 of 46 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-MDW
STL-ORD
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-MDW
STL-ORD
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 $300). Flying from St. Louis to Illinois in July is currently the most expensive (average of $451). 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 August 25, 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 August 25, 2026.
The most flights from STL to USIL are scheduled on a Sunday (66 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (43 on average).
How much does it cost to fly round-trip from St. Louis to Illinois?
Airfare is below average for this route at the moment.
St. Louis to Illinois flights typically cost between $214 and $502 in October.The cheapest round-trip price found within the last 5 days was $117 on United Airlines (Oct 1-Oct 5).
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 August 22, 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 August 25, 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
Entertainment
7.5
Comfort
8.0
Overall
8.0
Boarding
8.1
Crew
8.6
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Food
7.0
Entertainment
7.5
Comfort
8.0
Overall
8.0
Boarding
8.1
Crew
8.6
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Food
7.0
Entertainment
7.5
Comfort
8.0
Overall
8.0
Boarding
8.1
Crew
8.6
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Food
7.0
Entertainment
7.5
Comfort
8.0
Overall
8.0
Boarding
8.1
Crew
8.6
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Related info for your journey
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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 August 25, 2026.
Popular flight searches
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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 7,457,451 searches. Data last updated August 25, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$97 | Average$322 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$128 | Average$418 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$187 | Average$501 | FlexibilityNo cancel fee | On-time63% |