$40+ Cheap flights from Denver (DEN) 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 4/18. Fares are subject to change and may not be available on all flights or dates of travel.
DEN — ORD
May 2 — May 91
Round-trip
1 adult, Economy
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Cheapest flights from Denver to IllinoisExplore the most affordable flight options available from Denver to Illinois. Find the lowest fares from popular airlines and budget airlines, with prices last updated on April 2, 2026.
Explore the most affordable flight options available from Denver to Illinois. Find the lowest fares from popular airlines and budget airlines, with prices last updated on April 2, 2026.
This Cheapflightsfares deal was found by Cheapflights users on 3/31. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/2910:20 am
DEN
- PIA
Nonstop1h 59m
Allegiant Air
Sun 11/15:24 pm
PIA
- DEN
Nonstop2h 20m
Allegiant Air
Deal found 3/31![Allegiant Air logo]()
$102
This Super.com deal was found by Cheapflights users on 3/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 4/184:20 pm
DEN
- STL
Nonstop2h 12m
Frontier
Thu 4/239:55 pm
STL
- DEN
1 stop7h 04m
Frontier
Deal found 3/29![Frontier logo]()
$105
This Super.com deal was found by Cheapflights users on 3/31. Clicking the “Pick Dates” 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 5/44:20 pm
DEN
- STL
Nonstop2h 12m
Frontier
Fri 5/88:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 3/31![Frontier logo]()
$108
This Cheapflightsfares deal was found by Cheapflights users on 3/31. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/24:20 pm
DEN
- STL
Nonstop2h 12m
Frontier
Mon 5/49:55 pm
STL
- DEN
1 stop6h 30m
Frontier
Deal found 3/31![Frontier logo]()
$109
This Frontier deal was found by Cheapflights users on 3/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 5/610:29 pm
DEN
- STL
1 stop11h 52m
Frontier
Sat 5/98:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 3/30![Frontier logo]()
$110
This Frontier deal was found by Cheapflights users on 3/31. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 5/44:20 pm
DEN
- STL
Nonstop2h 12m
Frontier
Wed 5/66:51 pm
STL
- DEN
1 stop9h 34m
Frontier
Deal found 3/31![Frontier logo]()
$114
This Expedia deal was found by Cheapflights users on 3/31. Clicking the “Pick Dates” 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.
Fri 4/2411:59 pm
DEN
- STL
1 stop22h 20m
Frontier
Mon 4/278:17 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 3/31![Frontier logo]()
$116
This Cheapflightsfares deal was found by Cheapflights users on 3/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 4/184:20 pm
DEN
- STL
Nonstop2h 12m
Frontier
Mon 4/209:55 pm
STL
- DEN
1 stop27h 24m
Frontier
Deal found 3/30![Frontier logo]()
$118
This Cheapflightsfares deal was found by Cheapflights users on 3/28. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/174:09 pm
DEN
- STL
Nonstop2h 12m
Frontier
Sat 4/188:17 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 3/28![Frontier logo]()
$119
This Frontier deal was found by Cheapflights users on 3/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/74:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Mon 5/188:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 3/30![Frontier logo]()
$120
This Super.com deal was found by Cheapflights users on 3/31. Clicking the “Pick Dates” 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.
Sat 5/24:20 pm
DEN
- STL
Nonstop2h 12m
Frontier
Sun 5/38:06 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 3/31![Frontier logo]()
$123
This Booking.com deal was found by Cheapflights users on 3/31. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 5/244:27 pm
DEN
- PIA
Nonstop2h 03m
Allegiant Air
Sun 5/3111:09 am
PIA
- DEN
Nonstop2h 23m
Allegiant Air
Deal found 3/31![Allegiant Air logo]()
$153
Best flights from Denver to IllinoisDiscover carefully curated flight deals from Denver to Illinois that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated April 2, 2026.
Discover carefully curated flight deals from Denver to Illinois that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated April 2, 2026.
This United Airlines deal was found by Cheapflights users on 4/1. Clicking the “Pick Dates” 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 5/118:20 pm
DEN
- ORD
Nonstop2h 37m
United Airlines
Wed 5/139:54 pm
ORD
- DEN
Nonstop2h 56m
United Airlines
Deal found 4/1![United Airlines logo]()
$211
This Southwest deal was found by Cheapflights users on 4/1. Clicking the “Pick Dates” 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 4/223:05 pm
DEN
- ORD
1 stop6h 50m
Southwest
Sat 4/253:05 pm
ORD
- DEN
Nonstop3h 00m
Southwest
Deal found 4/1![Southwest logo]()
$221
This Delta deal was found by Cheapflights users on 3/31. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/1610:48 am
DEN
- MDW
1 stop6h 08m
Delta
Mon 5/187:13 pm
MDW
- DEN
1 stop5h 28m
Delta
Deal found 3/31![Delta logo]()
$239
This Kiwi.com deal was found by Cheapflights users on 3/31. Clicking the “Pick Dates” 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 4/2910:29 pm
DEN
- RFD
1 stop12h 31m
Multiple Airlines
Wed 5/612:09 pm
RFD
- DEN
1 stop11h 30m
Multiple Airlines
Deal found 3/31![Multiple Airlines logo]()
$256
This American Airlines deal was found by Cheapflights users on 3/28. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/1712:24 pm
DEN
- PIA
1 stop5h 00m
American Airlines
Sun 4/197:05 pm
PIA
- DEN
1 stop5h 54m
American Airlines
Deal found 3/28![American Airlines logo]()
$309
This Southwest deal was found by Cheapflights users on 3/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/78:20 pm
DEN
- MDW
Nonstop2h 20m
Southwest
Mon 5/119:35 pm
MDW
- DEN
Nonstop2h 40m
Southwest
Deal found 3/30![Southwest logo]()
$221
This Southwest deal was found by Cheapflights users on 4/1. Clicking the “Pick Dates” 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 4/2211:00 am
DEN
- MDW
2 stops5h 10m
Southwest
Sat 4/2510:10 am
MDW
- DEN
1 stop4h 30m
Southwest
Deal found 4/1![Southwest logo]()
$227
This United Airlines deal was found by Cheapflights users on 4/1. Clicking the “Pick Dates” 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 6/59:05 pm
DEN
- ORD
Nonstop2h 39m
United Airlines
Sun 6/75:00 am
ORD
- DEN
Nonstop2h 41m
United Airlines
Deal found 4/1![United Airlines logo]()
$266
This Delta deal was found by Cheapflights users on 3/28. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 5/1312:55 am
DEN
- ORD
1 stop6h 50m
Delta
Wed 5/208:05 pm
ORD
- DEN
1 stop4h 36m
Delta
Deal found 3/28![Delta logo]()
$277
This Southwest deal was found by Cheapflights users on 3/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/2711:25 am
DEN
- ORD
Nonstop2h 35m
Southwest
Mon 5/44:15 pm
ORD
- DEN
1 stop8h 30m
Southwest
Deal found 3/29![Southwest logo]()
$231
This United Airlines deal was found by Cheapflights users on 3/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/245:55 pm
DEN
- PIA
Nonstop2h 24m
United Airlines
Mon 4/275:35 pm
PIA
- DEN
1 stop7h 24m
United Airlines
Deal found 3/30![United Airlines logo]()
$279
This Southwest deal was found by Cheapflights users on 4/1. Clicking the “Pick Dates” 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 6/138:20 pm
DEN
- MDW
Nonstop2h 20m
Southwest
Tue 6/163:15 pm
MDW
- DEN
1 stop5h 05m
Southwest
Deal found 4/1![Southwest logo]()
$233
This Delta deal was found by Cheapflights users on 3/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 5/51:25 pm
DEN
- BMI
1 stop7h 56m
Delta
Tue 5/124:14 pm
BMI
- DEN
1 stop7h 09m
Delta
Deal found 3/29![Delta logo]()
$289
This American Airlines deal was found by Cheapflights users on 3/28. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/225:41 pm
DEN
- BMI
1 stop5h 18m
American Airlines
Wed 5/276:02 pm
BMI
- DEN
1 stop6h 57m
American Airlines
Deal found 3/28![American Airlines logo]()
$328
This Southwest deal was found by Cheapflights users on 4/1. Clicking the “Pick Dates” 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 4/306:35 am
DEN
- MDW
Nonstop2h 20m
Southwest
Sun 5/36:00 am
MDW
- DEN
Nonstop2h 40m
Southwest
Deal found 4/1![Southwest logo]()
$233
This Delta deal was found by Cheapflights users on 4/1. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/21:25 pm
DEN
- BMI
1 stop7h 56m
Delta
Tue 5/56:00 am
BMI
- DEN
1 stop8h 32m
Delta
Deal found 4/1![Delta logo]()
$289
This United Airlines deal was found by Cheapflights users on 4/1. Clicking the “Pick Dates” 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 5/45:34 pm
DEN
- STL
Nonstop2h 09m
United Airlines
Wed 5/68:46 am
STL
- DEN
Nonstop2h 34m
United Airlines
Deal found 4/1![United Airlines logo]()
$291
This American Airlines deal was found by Cheapflights users on 4/1. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/215:00 am
DEN
- BMI
1 stop6h 58m
American Airlines
Mon 5/256:02 pm
BMI
- DEN
1 stop6h 57m
American Airlines
Deal found 4/1![American Airlines logo]()
$328
This Kiwi.com deal was found by Cheapflights users on 3/31. Clicking the “Pick Dates” 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 4/1510:29 pm
DEN
- RFD
1 stop12h 31m
Multiple Airlines
Sun 4/1910:37 am
RFD
- DEN
2 stops26h 15m
Multiple Airlines
Deal found 3/31![Multiple Airlines logo]()
$366
This Southwest deal was found by Cheapflights users on 4/1. Clicking the “Pick Dates” 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 4/286:15 am
DEN
- ORD
1 stop5h 35m
Southwest
Thu 4/302:40 pm
ORD
- DEN
2 stops10h 05m
Southwest
Deal found 4/1![Southwest logo]()
$236
This Delta deal was found by Cheapflights users on 3/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/92:10 pm
DEN
- MLI
1 stop7h 11m
Delta
Mon 5/115:17 pm
MLI
- DEN
1 stop8h 16m
Delta
Deal found 3/29![Delta logo]()
$289
This United Airlines deal was found by Cheapflights users on 3/28. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/175:55 pm
DEN
- PIA
Nonstop2h 24m
United Airlines
Sun 4/197:43 pm
PIA
- DEN
1 stop6h 15m
United Airlines
Deal found 3/28![United Airlines logo]()
$299
This Kiwi.com deal was found by Cheapflights users on 3/31. Clicking the “Pick Dates” 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 5/89:03 am
DEN
- RFD
1 stop9h 42m
Multiple Airlines
Sun 5/1010:37 am
RFD
- DEN
2 stops12h 33m
Multiple Airlines
Deal found 3/31![Multiple Airlines logo]()
$375
This Southwest deal was found by Cheapflights users on 4/1. Clicking the “Pick Dates” 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 5/86:20 am
DEN
- STL
Nonstop2h 05m
Southwest
Mon 5/189:40 pm
STL
- DEN
Nonstop2h 20m
Southwest
Deal found 4/1![Southwest logo]()
$239
This American Airlines deal was found by Cheapflights users on 4/1. Clicking the “Pick Dates” 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 4/306:19 am
DEN
- CMI
1 stop6h 49m
American Airlines
Fri 5/16:58 pm
CMI
- DEN
1 stop6h 01m
American Airlines
Deal found 4/1![American Airlines logo]()
$356
This United Airlines deal was found by Cheapflights users on 3/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/175:55 pm
DEN
- PIA
Nonstop2h 24m
United Airlines
Fri 4/245:35 pm
PIA
- DEN
1 stop7h 24m
United Airlines
Deal found 3/29![United Airlines logo]()
$299
This Kiwi.com deal was found by Cheapflights users on 3/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/1411:30 am
DEN
- SPI
2 stops20h 56m
Multiple Airlines
Sat 4/1810:06 am
SPI
- DEN
1 stop13h 53m
Multiple Airlines
Deal found 3/30![Multiple Airlines logo]()
$376
This Southwest deal was found by Cheapflights users on 4/1. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/148:40 pm
DEN
- STL
Nonstop2h 10m
Southwest
Fri 5/159:40 pm
STL
- DEN
Nonstop2h 20m
Southwest
Deal found 4/1![Southwest logo]()
$239
This Delta deal was found by Cheapflights users on 3/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 5/135:45 am
DEN
- EVV
1 stop6h 17m
Delta
Sat 5/163:00 pm
EVV
- DEN
1 stop6h 01m
Delta
Deal found 3/30![Delta logo]()
$331
This United Airlines deal was found by Cheapflights users on 4/1. Clicking the “Pick Dates” 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 5/71:49 pm
DEN
- STL
Nonstop2h 08m
United Airlines
Mon 5/185:59 pm
STL
- DEN
Nonstop2h 34m
United Airlines
Deal found 4/1![United Airlines logo]()
$301
Last-minute flights from Denver to IllinoisDiscover last-minute flight deals from Denver to Illinois. Data last updated April 2, 2026 and is based on user searches.
Discover last-minute flight deals from Denver to Illinois. Data last updated April 2, 2026 and is based on user searches.
This Cheapflightsfares deal was found by Cheapflights users on 3/28. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/174:09 pm
DEN
- STL
Nonstop2h 12m
Frontier
Mon 4/208:17 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 3/28![Frontier logo]()
$119
This Super.com deal was found by Cheapflights users on 3/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 4/184:20 pm
DEN
- STL
Nonstop2h 12m
Frontier
Thu 4/239:55 pm
STL
- DEN
1 stop7h 04m
Frontier
Deal found 3/29![Frontier logo]()
$105
This Cheapflightsfares deal was found by Cheapflights users on 3/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 4/184:20 pm
DEN
- STL
Nonstop2h 12m
Frontier
Mon 4/209:55 pm
STL
- DEN
1 stop27h 24m
Frontier
Deal found 3/30![Frontier logo]()
$118
This Expedia deal was found by Cheapflights users on 3/31. Clicking the “Pick Dates” 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.
Fri 4/2411:59 pm
DEN
- STL
1 stop22h 20m
Frontier
Mon 4/278:17 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 3/31![Frontier logo]()
$116
This Cheapflightsfares deal was found by Cheapflights users on 3/31. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/24:20 pm
DEN
- STL
Nonstop2h 12m
Frontier
Mon 5/49:55 pm
STL
- DEN
1 stop6h 30m
Frontier
Deal found 3/31![Frontier logo]()
$109
This Super.com deal was found by Cheapflights users on 3/31. Clicking the “Pick Dates” 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.
Sat 5/24:20 pm
DEN
- STL
Nonstop2h 12m
Frontier
Sun 5/38:06 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 3/31![Frontier logo]()
$123
This Super.com deal was found by Cheapflights users on 3/31. Clicking the “Pick Dates” 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 5/44:20 pm
DEN
- STL
Nonstop2h 12m
Frontier
Fri 5/88:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 3/31![Frontier logo]()
$108
This Frontier deal was found by Cheapflights users on 3/31. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 5/44:20 pm
DEN
- STL
Nonstop2h 12m
Frontier
Wed 5/66:51 pm
STL
- DEN
1 stop9h 34m
Frontier
Deal found 3/31![Frontier logo]()
$114
This Frontier deal was found by Cheapflights users on 3/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 5/610:29 pm
DEN
- STL
1 stop11h 52m
Frontier
Sat 5/98:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 3/30![Frontier logo]()
$110
This Frontier deal was found by Cheapflights users on 3/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/74:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Mon 5/188:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 3/30![Frontier logo]()
$120
This Cheapflightsfares deal was found by Cheapflights users on 3/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/154:59 pm
DEN
- ORD
Nonstop2h 38m
Frontier
Sun 5/1710:22 am
ORD
- DEN
1 stop30h 40m
Frontier
Deal found 3/29![Frontier logo]()
$177
This Booking.com deal was found by Cheapflights users on 3/31. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 5/244:27 pm
DEN
- PIA
Nonstop2h 03m
Allegiant Air
Sun 5/3111:09 am
PIA
- DEN
Nonstop2h 23m
Allegiant Air
Deal found 3/31![Allegiant Air logo]()
$153
One-way flights from Denver to IllinoisSearch for one-way flight options from Denver to Illinois. Find affordable one-way fares based on user searches. Data last updated April 2, 2026.
Search for one-way flight options from Denver to Illinois. Find affordable one-way fares based on user searches. Data last updated April 2, 2026.
This Frontier deal was found by Cheapflights users on 3/31. Clicking the “Pick Dates” 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.
Sat 4/184:20 pm
DEN
- STL
Nonstop2h 12m
Frontier
Deal found 3/31![Frontier logo]()
$40
This Expedia deal was found by Cheapflights users on 3/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 6/154:12 pm
DEN
- STL
Nonstop2h 11m
Frontier
Deal found 3/30![Frontier logo]()
$44
This Frontier deal was found by Cheapflights users on 3/28. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 4/254:20 pm
DEN
- STL
Nonstop2h 12m
Frontier
Deal found 3/28![Frontier logo]()
$46
This Kiwi.com deal was found by Cheapflights users on 3/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/136:40 am
DEN
- STL
Nonstop2h 08m
Frontier
Deal found 3/30![Frontier logo]()
$48
This Super.com deal was found by Cheapflights users on 3/28. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/106:40 am
DEN
- STL
Nonstop2h 08m
Frontier
Deal found 3/28![Frontier logo]()
$58
This Frontier deal was found by Cheapflights users on 3/28. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/244:09 pm
DEN
- STL
Nonstop2h 12m
Frontier
Deal found 3/28![Frontier logo]()
$59
This Super.com deal was found by Cheapflights users on 3/31. Clicking the “Pick Dates” 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.
Fri 5/14:09 pm
DEN
- STL
Nonstop2h 12m
Frontier
Deal found 3/31![Frontier logo]()
$63
This Cheapflightsfares deal was found by Cheapflights users on 3/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/912:34 pm
DEN
- STL
1 stop6h 49m
Frontier
Deal found 3/30![Frontier logo]()
$70
This Kiwi.com deal was found by Cheapflights users on 3/28. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 4/264:09 pm
DEN
- STL
Nonstop2h 12m
Frontier
Deal found 3/28![Frontier logo]()
$72
This Super.com deal was found by Cheapflights users on 3/31. Clicking the “Pick Dates” 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 4/161:09 pm
DEN
- ORD
1 stop8h 30m
Frontier
Deal found 3/31![Frontier logo]()
$89
This Super.com deal was found by Cheapflights users on 3/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/11:00 pm
DEN
- MDW
1 stop8h 26m
Frontier
Deal found 3/29![Frontier logo]()
$89
This Cheapflightsfares deal was found by Cheapflights users on 3/31. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 5/187:00 am
DEN
- ORD
1 stop7h 43m
Frontier
Deal found 3/31![Frontier logo]()
$90
Find flight deals from Denver to Illinois
Keep the following information in mind while searching for Denver to Illinois flight deals. Data was last updated April 2, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $105 (Super.com) |
One-way from | $40 (Frontier) |
Popular in | March |
Cheapest in | August |
Average price | $225 |
Good round-trip deal | $265 or less |
Good one-way deal | $152 or less |
Cheapflights Fare Finder
Customize your flight search to find flights from Denver 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 April 2, 2026.
Use the filters below to find and compare flights from Denver to Illinois that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
DenverChicago
DEN - ORD
DENORD
Denver Intl
Mon 5/11
8:20 pm-11:57 pm
Nonstop2h 37m
Chicago O'Hare Intl
Wed 5/13
9:54 pm-11:50 pm
Nonstop2h 56m
$211
DenverChicago
DEN - ORD
DENORD
Denver Intl
Wed 4/22
3:05 pm-10:55 pm
1 stop6h 50m
Chicago O'Hare Intl
Sat 4/25
3:05 pm-5:05 pm
Nonstop3h 00m
$221
DenverChicago
DEN - MDW
DENMDW
Denver Intl
Thu 5/7
8:20 pm-11:40 pm
Nonstop2h 20m
Chicago Midway
Mon 5/11
9:35 pm-11:15 pm
Nonstop2h 40m
$221
DenverChicago
DEN - MDW
DENMDW
Denver Intl
Wed 4/22
11:00 am-5:10 pm
2 stops5h 10m
Chicago Midway
Sat 4/25
10:10 am-1:40 pm
1 stop4h 30m
$227
DenverChicago
DEN - ORD
DENORD
Denver Intl
Mon 4/27
11:25 am-3:00 pm
Nonstop2h 35m
Chicago O'Hare Intl
Mon 5/4
4:15 pm-11:45 pm
1 stop8h 30m
$231
DenverChicago
DEN - MDW
DENMDW
Denver Intl
Sat 6/13
8:20 pm-11:40 pm
Nonstop2h 20m
Chicago Midway
Tue 6/16
3:15 pm-7:20 pm
1 stop5h 05m
$233
DenverChicago
DEN - MDW
DENMDW
Denver Intl
Thu 4/30
6:35 am-9:55 am
Nonstop2h 20m
Chicago Midway
Sun 5/3
6:00 am-7:40 am
Nonstop2h 40m
$233
DenverChicago
DEN - ORD
DENORD
Denver Intl
Tue 4/28
6:15 am-12:50 pm
1 stop5h 35m
Chicago O'Hare Intl
Thu 4/30
2:40 pm-11:45 pm
2 stops10h 05m
$236
DenverChicago
DEN - MDW
DENMDW
Denver Intl
Sat 5/16
10:48 am-5:56 pm
1 stop6h 08m
Chicago Midway
Mon 5/18
7:13 pm-11:41 pm
1 stop5h 28m
$239
Quickest round-trip
DenverSt. Louis
DEN - STL
DENSTL
Denver Intl
Fri 5/8
6:20 am-9:25 am
Nonstop2h 05m
Lambert-St Louis
Mon 5/18
9:40 pm-11:00 pm
Nonstop2h 20m
$239
Showing 1-10 of 60 resultsSorted by cheapest first
Best time to book a flight from Denver to Illinois
Have a flexible travel schedule? Discover the best time to fly to Illinois from Denver with our price prediction graph.
DEN-STL
DEN-PIA
DEN-ORD
DEN-MDW
DEN-RFD
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 Denver to Illinois
DEN-USIL
DEN-STL
DEN-PIA
DEN-ORD
DEN-MDW
What is the cheapest month to book a flight from Denver to Illinois?
Currently, July is the cheapest month in which you can book a flight from Denver to Illinois (average of $46). Flying from Denver to Illinois in June is currently the most expensive (average of $140). 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 DEN to IL?
Find hourly flight availability from Denver 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 April 2, 2026.
It’s optimal to fly from Denver to Illinois in the morning. By choosing this option you can save up to 22% on the cost of your flight, compared to a flight at noon.
What is the cheapest day to fly from Denver to Illinois?
Use this chart to determine the cheapest time to fly round-trip from Denver to Illinois. Price data was last updated on May 11, 2025.
Travelers seeking maximum savings on their Denver to Illinois flight should consider departing on Friday at noon when fares are most often at their lowest. Wednesday at noon flights should be avoided if possible as fares are typically the most expensive at this time.
Weekly flight availability from Denver to Illinois
Explore weekly flight availability from Denver 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 April 2, 2026.
The most flights from DEN to USIL are scheduled on a Thursday (60 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (30 on average).
How much does it cost to fly round-trip from Denver to Illinois?
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 April 2, 2026.
Read through reviews of airlines operating flights from Denver to Illinois, such as Southwest,United Airlines, andAllegiant Air. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Entertainment
7.5
Food
7.0
Comfort
8.0
Boarding
8.1
Overall
8.0
Crew
8.6
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Entertainment
7.5
Food
7.0
Comfort
8.0
Boarding
8.1
Overall
8.0
Crew
8.6
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Entertainment
7.5
Food
7.0
Comfort
8.0
Boarding
8.1
Overall
8.0
Crew
8.6
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Entertainment
7.5
Food
7.0
Comfort
8.0
Boarding
8.1
Overall
8.0
Crew
8.6
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Entertainment
7.5
Food
7.0
Comfort
8.0
Boarding
8.1
Overall
8.0
Crew
8.6
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Entertainment
7.5
Food
7.0
Comfort
8.0
Boarding
8.1
Overall
8.0
Crew
8.6
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Related info for your journey
Find useful and relevant information for your journey from Denver 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 Denver to Illinois
See prices for flight routes from nearby airports that may be better suited for you.
Complete your trip
Complete your trip to Illinois by adding a car rental and/or hotel reservation to your travel itinerary.
Search flights from Denver to Illinois by cabin class
Find flights from Denver to Illinois, based on your preferred cabin class, be it economy, premium economy, business, or first class.
Denver and Illinois flights
Browse other Denver and Illinois flight options. Last updated on April 2, 2026.
Popular flight searches
Check out other popular destinations found by fellow travelers in 2026
Denver to Illinois flights
Consider these flights traveling from Denver to Illinois.
Top 6 airlines flying from Denver to Illinois
Discover the top 6 airlines that operate flights from Denver 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 April 2, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$57 | Average$137 | FlexibilityNo cancel fee | On-time88% | |
| Cheapest$75 | Average$186 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$126 | Average$191 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$155 | Average$269 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$157 | Average$398 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$163 | Average$359 | FlexibilityNo cancel fee | On-time69% |