$88+ 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 6/24. Fares are subject to change and may not be available on all flights or dates of travel.
DEN — ORD
Jun 3 — Jun 101
Round-trip
1 adult, Economy
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Find cheap flights from Denver to Illinois with Cheapflights
1. Tell us where you want to go
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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 May 4, 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 May 4, 2026.
This Kiwi.com deal was found by Cheapflights users on 4/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/305:05 am
DEN
- STL
1 stop13h 26m
Frontier
Wed 6/38:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 4/29![Frontier logo]()
$125
This Kiwi.com deal was found by Cheapflights users on 4/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 5/274:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Fri 5/299:06 pm
STL
- DEN
1 stop7h 19m
Frontier
Deal found 4/29![Frontier logo]()
$126
This Cheapflightsfares deal was found by Cheapflights users on 5/2. Clicking the “Pick Dates” 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.
Tue 5/264:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Tue 6/28:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 5/2![Frontier logo]()
$127
This Kiwi.com deal was found by Cheapflights users on 4/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/44:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Wed 6/108:08 pm
STL
- DEN
Nonstop2h 36m
Frontier
Deal found 4/29![Frontier logo]()
$129
This Kiwi.com deal was found by Cheapflights users on 5/1. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/34:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Tue 6/96:31 pm
STL
- DEN
1 stop15h 32m
Frontier
Deal found 5/1![Frontier logo]()
$130
This Cheapflightsfares deal was found by Cheapflights users on 4/29. 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.
Sun 5/244:27 pm
DEN
- PIA
Nonstop2h 03m
Allegiant Air
Sun 5/3111:09 am
PIA
- DEN
Nonstop2h 23m
Allegiant Air
Deal found 4/29![Allegiant Air logo]()
$131
This Cheapflightsfares deal was found by Cheapflights users on 4/30. 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.
Fri 5/224:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Tue 5/268:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 4/30![Frontier logo]()
$131
This Super.com deal was found by Cheapflights users on 5/2. Clicking the “Pick Dates” 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 5/274:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Sun 5/318:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 5/2![Frontier logo]()
$136
This Cheapflightsfares deal was found by Cheapflights users on 4/30. 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.
Tue 5/264:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Thu 5/288:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 4/30![Frontier logo]()
$137
This Frontier deal was found by Cheapflights users on 4/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/284:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Tue 6/28:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 4/29![Frontier logo]()
$138
This Cheapflightsfares deal was found by Cheapflights users on 5/2. Clicking the “Pick Dates” 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 5/214:27 pm
DEN
- PIA
Nonstop2h 03m
Allegiant Air
Sun 5/245:13 pm
PIA
- DEN
Nonstop2h 23m
Allegiant Air
Deal found 5/2![Allegiant Air logo]()
$177
This Kiwi.com deal was found by Cheapflights users on 4/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 5/244:27 pm
DEN
- PIA
Nonstop2h 03m
Multiple Airlines
Fri 5/297:59 pm
PIA
- DEN
1 stop13h 25m
Multiple Airlines
Deal found 4/29![Multiple Airlines logo]()
$182
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 May 4, 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 May 4, 2026.
This Southwest deal was found by Cheapflights users on 4/28. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 5/1911:25 am
DEN
- ORD
Nonstop2h 35m
Southwest
Sat 5/233:05 pm
ORD
- DEN
Nonstop3h 00m
Southwest
Deal found 4/28![Southwest logo]()
$211
This Trip.com deal was found by Cheapflights users on 5/3. Clicking the “Pick Dates” 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.
Sat 5/2310:00 am
DEN
- MDW
1 stop11h 02m
Frontier
Tue 5/266:00 am
MDW
- DEN
1 stop9h 04m
Frontier
Deal found 5/3![Frontier logo]()
$215
This Delta deal was found by Cheapflights users on 5/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 6/306:05 am
DEN
- ORD
1 stop5h 59m
Delta
Mon 7/65:30 am
ORD
- DEN
1 stop6h 37m
Delta
Deal found 5/2![Delta logo]()
$253
This United Airlines deal was found by Cheapflights users on 5/2. Clicking the “Pick Dates” 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 6/46:00 am
DEN
- ORD
Nonstop2h 38m
United Airlines
Sun 6/75:00 am
ORD
- DEN
Nonstop2h 42m
United Airlines
Deal found 5/2![United Airlines logo]()
$253
This American Airlines deal was found by Cheapflights users on 5/3. Clicking the “Pick Dates” 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 8/315:08 am
DEN
- CMI
1 stop8h 07m
American Airlines
Wed 9/92:47 pm
CMI
- DEN
1 stop7h 51m
American Airlines
Deal found 5/3![American Airlines logo]()
$284
This Kiwi.com deal was found by Cheapflights users on 5/2. Clicking the “Pick Dates” 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 6/177:43 am
DEN
- RFD
1 stop23h 46m
Multiple Airlines
Sat 7/410:05 am
RFD
- DEN
2 stops11h 01m
Multiple Airlines
Deal found 5/2![Multiple Airlines logo]()
$320
This Southwest deal was found by Cheapflights users on 4/29. 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 6/16:35 am
DEN
- MDW
Nonstop2h 20m
Southwest
Wed 6/38:50 pm
MDW
- DEN
Nonstop2h 45m
Southwest
Deal found 4/29![Southwest logo]()
$211
This Southwest deal was found by Cheapflights users on 5/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 6/198:50 pm
DEN
- MDW
Nonstop2h 20m
Southwest
Tue 6/235:30 am
MDW
- DEN
Nonstop2h 35m
Southwest
Deal found 5/3![Southwest logo]()
$233
This Delta deal was found by Cheapflights users on 4/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/2810:27 am
DEN
- MDW
1 stop7h 06m
Delta
Sun 5/319:22 am
MDW
- DEN
1 stop5h 37m
Delta
Deal found 4/29![Delta logo]()
$262
This United Airlines deal was found by Cheapflights users on 4/30. 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.
Thu 7/239:05 pm
DEN
- ORD
Nonstop2h 39m
United Airlines
Thu 7/305:00 am
ORD
- DEN
Nonstop2h 42m
United Airlines
Deal found 4/30![United Airlines logo]()
$265
This Southwest deal was found by Cheapflights users on 4/30. 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.
Tue 6/26:35 am
DEN
- MDW
Nonstop2h 20m
Southwest
Sat 6/207:20 am
MDW
- DEN
Nonstop2h 35m
Southwest
Deal found 4/30![Southwest logo]()
$233
This United Airlines deal was found by Cheapflights users on 4/30. 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.
Sat 6/139:05 pm
DEN
- ORD
Nonstop2h 39m
United Airlines
Sun 6/145:00 am
ORD
- DEN
Nonstop2h 41m
United Airlines
Deal found 4/30![United Airlines logo]()
$265
This American Airlines deal was found by Cheapflights users on 4/29. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/283:11 pm
DEN
- CMI
1 stop5h 50m
American Airlines
Sun 5/316:39 pm
CMI
- DEN
1 stop6h 20m
American Airlines
Deal found 4/29![American Airlines logo]()
$298
This Delta deal was found by Cheapflights users on 4/30. 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.
Mon 7/66:00 am
DEN
- ORD
1 stop4h 31m
Delta
Wed 7/223:22 pm
ORD
- DEN
1 stop6h 31m
Delta
Deal found 4/30![Delta logo]()
$275
This United Airlines deal was found by Cheapflights users on 4/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 6/229:05 pm
DEN
- ORD
Nonstop2h 39m
United Airlines
Fri 6/2611:00 pm
ORD
- DEN
Nonstop2h 58m
United Airlines
Deal found 4/29![United Airlines logo]()
$265
This Kiwi.com deal was found by Cheapflights users on 4/30. 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.
Wed 6/177:43 am
DEN
- RFD
1 stop23h 46m
Multiple Airlines
Mon 6/227:53 pm
RFD
- DEN
2 stops19h 06m
Multiple Airlines
Deal found 4/30![Multiple Airlines logo]()
$327
This Delta deal was found by Cheapflights users on 5/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/31:15 pm
DEN
- MDW
1 stop8h 02m
Delta
Wed 7/81:49 pm
MDW
- DEN
1 stop7h 07m
Delta
Deal found 5/3![Delta logo]()
$275
This Southwest deal was found by Cheapflights users on 5/1. 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.
Sun 5/247:15 am
DEN
- MDW
Nonstop2h 25m
Southwest
Tue 5/266:30 am
MDW
- DEN
Nonstop2h 40m
Southwest
Deal found 5/1![Southwest logo]()
$251
This American Airlines deal was found by Cheapflights users on 5/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 6/207:13 am
DEN
- CMI
1 stop6h 02m
American Airlines
Wed 6/246:43 pm
CMI
- DEN
1 stop6h 34m
American Airlines
Deal found 5/3![American Airlines logo]()
$306
This Kiwi.com deal was found by Cheapflights users on 5/3. Clicking the “Pick Dates” 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 6/184:50 pm
DEN
- PIA
Nonstop2h 06m
Multiple Airlines
Sun 6/217:50 pm
PIA
- DEN
2 stops26h 59m
Multiple Airlines
Deal found 5/3![Multiple Airlines logo]()
$333
This United Airlines deal was found by Cheapflights users on 5/1. 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 5/295:38 pm
DEN
- MLI
Nonstop2h 16m
United Airlines
Mon 6/16:30 pm
MLI
- DEN
1 stop6h 22m
United Airlines
Deal found 5/1![United Airlines logo]()
$279
This Delta deal was found by Cheapflights users on 4/30. 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.
Mon 7/66:05 am
DEN
- ORD
1 stop5h 55m
Delta
Mon 7/205:54 pm
ORD
- DEN
1 stop6h 33m
Delta
Deal found 4/30![Delta logo]()
$285
This Southwest deal was found by Cheapflights users on 5/2. Clicking the “Pick Dates” 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 7/712:20 pm
DEN
- MDW
1 stop3h 45m
Southwest
Mon 7/135:15 am
MDW
- DEN
Nonstop2h 35m
Southwest
Deal found 5/2![Southwest logo]()
$261
This American Airlines deal was found by Cheapflights users on 5/3. Clicking the “Pick Dates” 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 5/182:41 pm
DEN
- BMI
1 stop6h 46m
American Airlines
Sun 5/246:48 am
BMI
- DEN
1 stop6h 01m
American Airlines
Deal found 5/3![American Airlines logo]()
$324
This Kiwi.com deal was found by Cheapflights users on 5/2. Clicking the “Pick Dates” 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 6/510:34 pm
DEN
- RFD
1 stop12h 40m
Multiple Airlines
Mon 6/89:10 pm
RFD
- DEN
1 stop21h 00m
Multiple Airlines
Deal found 5/2![Multiple Airlines logo]()
$347
This Southwest deal was found by Cheapflights users on 4/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/1512:20 pm
DEN
- MDW
1 stop3h 45m
Southwest
Sun 7/195:25 am
MDW
- DEN
Nonstop2h 35m
Southwest
Deal found 4/29![Southwest logo]()
$261
This Delta deal was found by Cheapflights users on 4/29. 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.
Wed 5/277:05 am
DEN
- MLI
1 stop8h 32m
Delta
Sun 5/315:17 pm
MLI
- DEN
1 stop8h 16m
Delta
Deal found 4/29![Delta logo]()
$289
This United Airlines deal was found by Cheapflights users on 5/1. 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.
Sat 9/55:29 pm
DEN
- PIA
Nonstop2h 18m
United Airlines
Mon 9/75:31 pm
PIA
- DEN
1 stop7h 03m
United Airlines
Deal found 5/1![United Airlines logo]()
$291
This Delta deal was found by Cheapflights users on 5/3. Clicking the “Pick Dates” 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 7/22:15 pm
DEN
- MLI
1 stop7h 19m
Delta
Mon 7/65:56 am
MLI
- DEN
1 stop6h 11m
Delta
Deal found 5/3![Delta logo]()
$289
This United Airlines deal was found by Cheapflights users on 5/3. Clicking the “Pick Dates” 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 9/285:32 pm
DEN
- STL
Nonstop2h 05m
United Airlines
Wed 9/308:15 pm
STL
- DEN
1 stop5h 43m
United Airlines
Deal found 5/3![United Airlines logo]()
$294
Last-minute flights from Denver to IllinoisDiscover last-minute flight deals from Denver to Illinois. Data last updated May 4, 2026 and is based on user searches.
Discover last-minute flight deals from Denver to Illinois. Data last updated May 4, 2026 and is based on user searches.
This Cheapflightsfares deal was found by Cheapflights users on 5/2. Clicking the “Pick Dates” 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 5/214:27 pm
DEN
- PIA
Nonstop2h 03m
Allegiant Air
Sun 5/245:13 pm
PIA
- DEN
Nonstop2h 23m
Allegiant Air
Deal found 5/2![Allegiant Air logo]()
$177
This Cheapflightsfares deal was found by Cheapflights users on 4/30. 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.
Fri 5/224:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Tue 5/268:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 4/30![Frontier logo]()
$131
This Frontier deal was found by Cheapflights users on 4/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/239:52 am
DEN
- STL
1 stop8h 39m
Frontier
Tue 5/266:51 pm
STL
- DEN
1 stop9h 34m
Frontier
Deal found 4/29![Frontier logo]()
$140
This Cheapflightsfares deal was found by Cheapflights users on 4/29. 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.
Sun 5/244:27 pm
DEN
- PIA
Nonstop2h 03m
Allegiant Air
Sun 5/3111:09 am
PIA
- DEN
Nonstop2h 23m
Allegiant Air
Deal found 4/29![Allegiant Air logo]()
$131
This Kiwi.com deal was found by Cheapflights users on 4/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 5/244:27 pm
DEN
- PIA
Nonstop2h 03m
Multiple Airlines
Fri 5/297:59 pm
PIA
- DEN
1 stop13h 25m
Multiple Airlines
Deal found 4/29![Multiple Airlines logo]()
$182
This Cheapflightsfares deal was found by Cheapflights users on 5/2. Clicking the “Pick Dates” 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.
Tue 5/264:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Tue 6/28:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 5/2![Frontier logo]()
$127
This Cheapflightsfares deal was found by Cheapflights users on 4/30. 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.
Tue 5/264:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Thu 5/288:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 4/30![Frontier logo]()
$137
This Kiwi.com deal was found by Cheapflights users on 4/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 5/274:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Fri 5/299:06 pm
STL
- DEN
1 stop7h 19m
Frontier
Deal found 4/29![Frontier logo]()
$126
This Super.com deal was found by Cheapflights users on 5/2. Clicking the “Pick Dates” 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 5/274:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Sun 5/318:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 5/2![Frontier logo]()
$136
This Frontier deal was found by Cheapflights users on 4/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/284:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Tue 6/28:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 4/29![Frontier logo]()
$138
This Frontier deal was found by Cheapflights users on 4/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/2911:54 pm
DEN
- STL
1 stop8h 01m
Frontier
Wed 6/38:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 4/29![Frontier logo]()
$139
This Kiwi.com deal was found by Cheapflights users on 4/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/305:05 am
DEN
- STL
1 stop13h 26m
Frontier
Wed 6/38:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 4/29![Frontier logo]()
$125
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 May 4, 2026.
Search for one-way flight options from Denver to Illinois. Find affordable one-way fares based on user searches. Data last updated May 4, 2026.
This Kiwi.com deal was found by Cheapflights users on 4/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/2410:09 am
DEN
- STL
1 stop7h 09m
Frontier
Deal found 4/29![Frontier logo]()
$88
This Super.com deal was found by Cheapflights users on 4/29. 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.
Sun 6/711:54 pm
DEN
- ORD
1 stop7h 01m
Frontier
Deal found 4/29![Frontier logo]()
$89
This Super.com deal was found by Cheapflights users on 5/2. Clicking the “Pick Dates” 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.
Tue 5/197:00 am
DEN
- MDW
1 stop6h 12m
Frontier
Deal found 5/2![Frontier logo]()
$89
This Kiwi.com deal was found by Cheapflights users on 5/1. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 5/2711:54 pm
DEN
- STL
1 stop16h 39m
Frontier
Deal found 5/1![Frontier logo]()
$89
This Cheapflightsfares deal was found by Cheapflights users on 4/30. 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.
Mon 5/1810:00 am
DEN
- ORD
1 stop8h 51m
Frontier
Deal found 4/30![Frontier logo]()
$90
This Frontier deal was found by Cheapflights users on 4/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/2811:54 pm
DEN
- STL
1 stop8h 01m
Frontier
Deal found 4/29![Frontier logo]()
$90
This Frontier deal was found by Cheapflights users on 4/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/84:54 pm
DEN
- ORD
Nonstop2h 38m
Frontier
Deal found 4/29![Frontier logo]()
$91
This Kiwi.com deal was found by Cheapflights users on 4/30. 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.
Wed 6/2410:09 am
DEN
- MDW
1 stop28h 06m
Frontier
Deal found 4/30![Frontier logo]()
$91
This Mytrip deal was found by Cheapflights users on 5/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 6/112:34 pm
DEN
- STL
1 stop6h 37m
Frontier
Deal found 5/2![Frontier logo]()
$91
This Kiwi.com deal was found by Cheapflights users on 4/30. 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 5/2610:00 am
DEN
- ORD
1 stop20h 55m
Frontier
Deal found 4/30![Frontier logo]()
$93
This Kiwi.com deal was found by Cheapflights users on 4/30. 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.
Wed 5/276:30 am
DEN
- MDW
1 stop14h 32m
Frontier
Deal found 4/30![Frontier logo]()
$93
This Super.com deal was found by Cheapflights users on 4/30. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 5/184:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Deal found 4/30![Frontier logo]()
$93
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 May 4, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $125 (Kiwi.com) |
One-way from | $70 (Cheapflightsfares) |
Popular in | March |
Cheapest in | August |
Average price | $249 |
Good round-trip deal | $284 or less |
Good one-way deal | $74 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 May 4, 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
Tue 5/19
11:25 am-3:00 pm
Nonstop2h 35m
Chicago O'Hare Intl
Sat 5/23
3:05 pm-5:05 pm
Nonstop3h 00m
$211
DenverChicago
DEN - MDW
DENMDW
Denver Intl
Mon 6/1
6:35 am-9:55 am
Nonstop2h 20m
Chicago Midway
Wed 6/3
8:50 pm-10:35 pm
Nonstop2h 45m
$211
DenverChicago
DEN - MDW
DENMDW
Denver Intl
Sat 5/23
10:00 am-10:02 pm
1 stop11h 02m
Chicago Midway
Tue 5/26
6:00 am-2:04 pm
1 stop9h 04m
$215
Quickest round-trip
DenverChicago
DEN - MDW
DENMDW
Denver Intl
Fri 6/19
8:50 pm-12:10 am
Nonstop2h 20m
Chicago Midway
Tue 6/23
5:30 am-7:05 am
Nonstop2h 35m
$233
DenverChicago
DEN - MDW
DENMDW
Denver Intl
Tue 6/2
6:35 am-9:55 am
Nonstop2h 20m
Chicago Midway
Sat 6/20
7:20 am-8:55 am
Nonstop2h 35m
$233
DenverChicago
DEN - MDW
DENMDW
Denver Intl
Sun 5/24
7:15 am-10:40 am
Nonstop2h 25m
Chicago Midway
Tue 5/26
6:30 am-8:10 am
Nonstop2h 40m
$251
DenverChicago
DEN - ORD
DENORD
Denver Intl
Tue 6/30
6:05 am-1:04 pm
1 stop5h 59m
Chicago O'Hare Intl
Mon 7/6
5:30 am-11:07 am
1 stop6h 37m
$253
DenverChicago
DEN - ORD
DENORD
Denver Intl
Thu 6/4
6:00 am-9:38 am
Nonstop2h 38m
Chicago O'Hare Intl
Sun 6/7
5:00 am-6:42 am
Nonstop2h 42m
$253
DenverChicago
DEN - MDW
DENMDW
Denver Intl
Tue 7/7
12:20 pm-5:05 pm
1 stop3h 45m
Chicago Midway
Mon 7/13
5:15 am-6:50 am
Nonstop2h 35m
$261
DenverChicago
DEN - MDW
DENMDW
Denver Intl
Wed 7/15
12:20 pm-5:05 pm
1 stop3h 45m
Chicago Midway
Sun 7/19
5:25 am-7:00 am
Nonstop2h 35m
$261
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-MDW
DEN-STL
DEN-RFD
DEN-ORD
DEN-PIA
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-MDW
DEN-STL
DEN-RFD
DEN-ORD
How far ahead should I book a flight from Denver to Illinois?
To ensure you get the cheapest price possible for a flight from Denver to Illinois, you should look to book at least 78 days in advance of your intended travel date. The price of your flight may increase if you delay and leave booking until a week or so before departure.
What is the cheapest month to book a flight from Denver to Illinois?
Currently, August is the cheapest month in which you can book a flight from Denver to Illinois (average of $218). Flying from Denver to Illinois in December is currently the most expensive (average of $460). 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 May 4, 2026.
It’s optimal to fly from Denver to Illinois in the morning. By choosing this option you can save up to 25% on the cost of your flight, compared to a flight in the afternoon.
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. Sunday afternoons 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 May 4, 2026.
The most flights from DEN to USIL are scheduled on a Monday (69 on average). You will have fewer flight options on Sunday, which is when the least amount of flights are scheduled (58 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 May 4, 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.
Overall
7.9
Entertainment
7.5
Comfort
8.0
Crew
8.6
Food
7.0
Boarding
8.1
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Overall
7.9
Entertainment
7.5
Comfort
8.0
Crew
8.6
Food
7.0
Boarding
8.1
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Overall
7.9
Entertainment
7.5
Comfort
8.0
Crew
8.6
Food
7.0
Boarding
8.1
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Overall
7.9
Entertainment
7.5
Comfort
8.0
Crew
8.6
Food
7.0
Boarding
8.1
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Overall
7.9
Entertainment
7.5
Comfort
8.0
Crew
8.6
Food
7.0
Boarding
8.1
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Overall
7.9
Entertainment
7.5
Comfort
8.0
Crew
8.6
Food
7.0
Boarding
8.1
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.
Browse thousands of different options on Cheapflights for your next trip
Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.
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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 May 4, 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 May 4, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$63 | Average$146 | FlexibilityNo cancel fee | On-time88% | |
| Cheapest$75 | Average$186 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$126 | Average$191 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$157 | Average$278 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$159 | Average$401 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$168 | Average$358 | FlexibilityNo cancel fee | On-time69% |