$87+ 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 10/1. Fares are subject to change and may not be available on all flights or dates of travel.
DEN — ORD
Jul 4 — Jul 111
Round-trip
1 adult, Economy
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Find cheap flights from Denver to Illinois with Cheapflights
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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 June 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 June 4, 2026.
This Booking.com deal was found by Cheapflights users on 5/31. 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.
Thu 8/64:27 pm
DEN
- PIA
Nonstop2h 10m
Allegiant Air
Sun 8/95:23 pm
PIA
- DEN
Nonstop2h 25m
Allegiant Air
Deal found 5/31![Allegiant Air logo]()
$110
This Cheapflightsfares deal was found by Cheapflights users on 5/31. 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 9/102:16 pm
DEN
- PIA
Nonstop2h 03m
Allegiant Air
Sun 9/1310:07 am
PIA
- DEN
Nonstop2h 20m
Allegiant Air
Deal found 5/31![Allegiant Air logo]()
$128
This Super.com deal was found by Cheapflights users on 6/3. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/204:12 pm
DEN
- STL
Nonstop2h 11m
Frontier
Sun 8/238:08 pm
STL
- DEN
Nonstop2h 36m
Frontier
Deal found 6/3![Frontier logo]()
$161
This Cheapflightsfares deal was found by Cheapflights users on 6/3. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/174:10 pm
DEN
- STL
Nonstop2h 13m
Frontier
Wed 9/24:10 pm
STL
- DEN
1 stop7h 44m
Frontier
Deal found 6/3![Frontier logo]()
$163
This Cheapflightsfares deal was found by Cheapflights users on 6/3. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 6/273:41 pm
DEN
- STL
Nonstop2h 12m
Frontier
Tue 6/308:08 pm
STL
- DEN
Nonstop2h 36m
Frontier
Deal found 6/3![Frontier logo]()
$166
This Frontier deal was found by Cheapflights users on 6/1. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/244:12 pm
DEN
- STL
Nonstop2h 11m
Frontier
Tue 6/308:08 pm
STL
- DEN
Nonstop2h 36m
Frontier
Deal found 6/1![Frontier logo]()
$170
This Kiwi.com deal was found by Cheapflights users on 6/3. 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 8/65:05 am
DEN
- STL
1 stop8h 51m
Frontier
Mon 8/108:08 pm
STL
- DEN
Nonstop2h 36m
Frontier
Deal found 6/3![Frontier logo]()
$171
This Kiwi.com deal was found by Cheapflights users on 6/3. 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.
Tue 8/114:10 pm
DEN
- STL
Nonstop2h 13m
Frontier
Sun 8/166:34 pm
STL
- DEN
1 stop15h 29m
Frontier
Deal found 6/3![Frontier logo]()
$172
This Cheapflightsfares deal was found by Cheapflights users on 6/3. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/64:10 pm
DEN
- STL
Nonstop2h 13m
Frontier
Sun 8/98:08 pm
STL
- DEN
Nonstop2h 36m
Frontier
Deal found 6/3![Frontier logo]()
$173
This Super.com deal was found by Cheapflights users on 6/3. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/94:10 pm
DEN
- STL
Nonstop2h 13m
Frontier
Sat 8/158:08 pm
STL
- DEN
Nonstop2h 36m
Frontier
Deal found 6/3![Frontier logo]()
$174
This Cheapflightsfares deal was found by Cheapflights users on 6/4. Clicking the “Pick Dates” 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.
Wed 7/14:12 pm
DEN
- STL
Nonstop2h 11m
Frontier
Tue 7/78:08 pm
STL
- DEN
Nonstop2h 36m
Frontier
Deal found 6/4![Frontier logo]()
$181
This Kiwi.com deal was found by Cheapflights users on 6/3. 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.
Tue 7/146:30 am
DEN
- ORD
1 stop12h 23m
Frontier
Wed 7/221:50 pm
ORD
- DEN
1 stop9h 15m
Frontier
Deal found 6/3![Frontier logo]()
$184
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 June 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 June 4, 2026.
This United Airlines deal was found by Cheapflights users on 6/1. 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 8/138:29 pm
DEN
- ORD
Nonstop2h 30m
United Airlines
Tue 8/181:30 pm
ORD
- DEN
Nonstop2h 47m
United Airlines
Deal found 6/1![United Airlines logo]()
$227
This Southwest deal was found by Cheapflights users on 6/2. 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.
Thu 8/68:25 pm
DEN
- MDW
Nonstop2h 20m
Southwest
Wed 8/126:40 am
MDW
- DEN
Nonstop2h 30m
Southwest
Deal found 6/2![Southwest logo]()
$227
This Delta deal was found by Cheapflights users on 6/2. 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.
Wed 9/911:15 am
DEN
- ORD
1 stop4h 33m
Delta
Mon 9/145:42 pm
ORD
- DEN
1 stop6h 43m
Delta
Deal found 6/2![Delta logo]()
$247
This Kiwi.com deal was found by Cheapflights users on 6/2. 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.
Thu 8/277:23 am
DEN
- RFD
1 stop6h 46m
Multiple Airlines
Sun 8/309:35 pm
RFD
- DEN
1 stop7h 23m
Multiple Airlines
Deal found 6/2![Multiple Airlines logo]()
$300
This American Airlines deal was found by Cheapflights users on 6/2. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/17:13 am
DEN
- CMI
1 stop6h 02m
American Airlines
Tue 7/76:36 pm
CMI
- DEN
1 stop6h 41m
American Airlines
Deal found 6/2![American Airlines logo]()
$306
This Southwest deal was found by Cheapflights users on 6/3. 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.
Sat 11/76:35 am
DEN
- MDW
Nonstop2h 20m
Southwest
Mon 11/95:55 am
MDW
- DEN
Nonstop2h 50m
Southwest
Deal found 6/3![Southwest logo]()
$237
This United Airlines deal was found by Cheapflights users on 6/3. 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.
Wed 8/59:05 pm
DEN
- ORD
Nonstop2h 39m
United Airlines
Sun 8/95:00 am
ORD
- DEN
Nonstop2h 41m
United Airlines
Deal found 6/3![United Airlines logo]()
$241
This Delta deal was found by Cheapflights users on 6/1. 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 10/1011:10 am
DEN
- ORD
1 stop4h 39m
Delta
Tue 10/136:00 am
ORD
- DEN
1 stop7h 03m
Delta
Deal found 6/1![Delta logo]()
$247
This Southwest deal was found by Cheapflights users on 5/30. 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.
Wed 8/56:35 am
DEN
- STL
Nonstop2h 00m
Southwest
Wed 8/56:30 pm
STL
- DEN
Nonstop2h 15m
Southwest
Deal found 5/30![Southwest logo]()
$237
This Delta deal was found by Cheapflights users on 5/31. 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.
Wed 10/710:30 am
DEN
- ORD
1 stop7h 10m
Delta
Sat 10/108:55 am
ORD
- DEN
1 stop6h 08m
Delta
Deal found 5/31![Delta logo]()
$247
This United Airlines deal was found by Cheapflights users on 5/30. 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.
Tue 8/111:27 pm
DEN
- STL
Nonstop2h 07m
United Airlines
Mon 8/175:30 pm
STL
- DEN
1 stop5h 14m
United Airlines
Deal found 5/30![United Airlines logo]()
$247
This Delta deal was found by Cheapflights users on 6/3. 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.
Wed 11/116:45 am
DEN
- MDW
1 stop4h 48m
Delta
Mon 11/169:30 am
MDW
- DEN
1 stop5h 33m
Delta
Deal found 6/3![Delta logo]()
$247
This Southwest deal was found by Cheapflights users on 6/3. 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.
Wed 8/511:15 am
DEN
- MDW
1 stop3h 45m
Southwest
Sun 8/96:30 am
MDW
- DEN
Nonstop2h 30m
Southwest
Deal found 6/3![Southwest logo]()
$247
This United Airlines deal was found by Cheapflights users on 5/30. 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 9/48:29 pm
DEN
- ORD
Nonstop2h 30m
United Airlines
Mon 9/710:00 pm
ORD
- DEN
Nonstop2h 53m
United Airlines
Deal found 5/30![United Airlines logo]()
$251
This American Airlines deal was found by Cheapflights users on 6/3. 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.
Wed 7/16:22 am
DEN
- CMI
1 stop6h 53m
American Airlines
Wed 7/86:36 pm
CMI
- DEN
1 stop6h 41m
American Airlines
Deal found 6/3![American Airlines logo]()
$306
This Kiwi.com deal was found by Cheapflights users on 5/31. 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.
Mon 8/179:15 am
DEN
- RFD
1 stop10h 19m
Multiple Airlines
Sun 8/239:35 pm
RFD
- DEN
1 stop7h 23m
Multiple Airlines
Deal found 5/31![Multiple Airlines logo]()
$320
This American Airlines deal was found by Cheapflights users on 6/2. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/35:57 pm
DEN
- BMI
1 stop5h 38m
American Airlines
Tue 7/76:04 pm
BMI
- DEN
1 stop7h 13m
American Airlines
Deal found 6/2![American Airlines logo]()
$309
This Delta deal was found by Cheapflights users on 6/2. 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.
Sat 9/1211:15 am
DEN
- ORD
1 stop4h 33m
Delta
Sat 9/197:01 am
ORD
- DEN
1 stop7h 50m
Delta
Deal found 6/2![Delta logo]()
$257
This Southwest deal was found by Cheapflights users on 6/2. 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.
Sun 8/166:10 am
DEN
- MDW
Nonstop2h 25m
Southwest
Sat 8/222:15 pm
MDW
- DEN
1 stop5h 15m
Southwest
Deal found 6/2![Southwest logo]()
$257
This United Airlines deal was found by Cheapflights users on 6/1. 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.
Wed 10/216:00 pm
DEN
- MLI
Nonstop2h 03m
United Airlines
Sat 10/242:28 pm
MLI
- DEN
1 stop6h 17m
United Airlines
Deal found 6/1![United Airlines logo]()
$279
This Delta deal was found by Cheapflights users on 6/2. 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.
Sat 8/157:05 am
DEN
- STL
1 stop5h 29m
Delta
Mon 8/177:00 am
STL
- DEN
1 stop7h 17m
Delta
Deal found 6/2![Delta logo]()
$257
This Southwest deal was found by Cheapflights users on 5/31. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/248:50 pm
DEN
- MDW
Nonstop2h 25m
Southwest
Mon 7/275:15 am
MDW
- DEN
Nonstop2h 35m
Southwest
Deal found 5/31![Southwest logo]()
$265
This Kiwi.com deal was found by Cheapflights users on 6/3. 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.
Wed 6/247:43 am
DEN
- RFD
1 stop23h 46m
Multiple Airlines
Sun 6/289:19 am
RFD
- DEN
1 stop6h 01m
Multiple Airlines
Deal found 6/3![Multiple Airlines logo]()
$355
This American Airlines deal was found by Cheapflights users on 6/1. 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.
Sat 6/207:13 am
DEN
- BMI
1 stop7h 39m
American Airlines
Wed 6/246:02 pm
BMI
- DEN
1 stop7h 15m
American Airlines
Deal found 6/1![American Airlines logo]()
$324
This Delta deal was found by Cheapflights users on 6/3. 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.
Wed 8/2610:26 am
DEN
- MDW
1 stop7h 07m
Delta
Fri 8/286:42 pm
MDW
- DEN
1 stop5h 06m
Delta
Deal found 6/3![Delta logo]()
$261
This Southwest deal was found by Cheapflights users on 5/31. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/226:15 am
DEN
- MDW
Nonstop2h 25m
Southwest
Sat 7/254:05 pm
MDW
- DEN
1 stop4h 40m
Southwest
Deal found 5/31![Southwest logo]()
$265
This Kiwi.com deal was found by Cheapflights users on 6/1. 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 7/299:15 am
DEN
- RFD
1 stop9h 44m
Multiple Airlines
Thu 7/309:19 am
RFD
- DEN
1 stop6h 04m
Multiple Airlines
Deal found 6/1![Multiple Airlines logo]()
$362
This American Airlines deal was found by Cheapflights users on 6/1. 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.
Mon 6/297:13 am
DEN
- BMI
1 stop7h 39m
American Airlines
Mon 7/65:45 pm
BMI
- DEN
1 stop7h 32m
American Airlines
Deal found 6/1![American Airlines logo]()
$339
This Delta deal was found by Cheapflights users on 6/1. 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.
Fri 7/1712:59 am
DEN
- MDW
1 stop7h 14m
Delta
Tue 7/217:06 pm
MDW
- DEN
1 stop5h 21m
Delta
Deal found 6/1![Delta logo]()
$261
This Southwest deal was found by Cheapflights users on 5/31. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/2511:00 am
DEN
- MDW
1 stop5h 00m
Southwest
Sun 9/277:55 am
MDW
- DEN
Nonstop2h 45m
Southwest
Deal found 5/31![Southwest logo]()
$275
Last-minute flights from Denver to IllinoisDiscover last-minute flight deals from Denver to Illinois. Data last updated June 4, 2026 and is based on user searches.
Discover last-minute flight deals from Denver to Illinois. Data last updated June 4, 2026 and is based on user searches.
This Frontier deal was found by Cheapflights users on 6/1. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/244:12 pm
DEN
- STL
Nonstop2h 11m
Frontier
Tue 6/308:08 pm
STL
- DEN
Nonstop2h 36m
Frontier
Deal found 6/1![Frontier logo]()
$170
This Frontier deal was found by Cheapflights users on 6/1. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/2411:46 pm
DEN
- ORD
1 stop7h 17m
Frontier
Sat 6/279:48 pm
ORD
- DEN
Nonstop3h 06m
Frontier
Deal found 6/1![Frontier logo]()
$189
This Cheapflightsfares deal was found by Cheapflights users on 6/3. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/255:05 pm
DEN
- ORD
Nonstop2h 38m
Frontier
Sat 6/279:48 pm
ORD
- DEN
Nonstop3h 06m
Frontier
Deal found 6/3![Frontier logo]()
$190
This Cheapflightsfares deal was found by Cheapflights users on 6/3. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 6/273:41 pm
DEN
- STL
Nonstop2h 12m
Frontier
Tue 6/308:08 pm
STL
- DEN
Nonstop2h 36m
Frontier
Deal found 6/3![Frontier logo]()
$166
This Cheapflightsfares deal was found by Cheapflights users on 6/3. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 7/49:06 pm
DEN
- ORD
1 stop26h 43m
Frontier
Wed 7/89:57 pm
ORD
- DEN
Nonstop3h 00m
Frontier
Deal found 6/3![Frontier logo]()
$191
This Super.com deal was found by Cheapflights users on 6/1. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/74:10 pm
DEN
- STL
Nonstop2h 13m
Frontier
Sat 7/118:08 pm
STL
- DEN
Nonstop2h 36m
Frontier
Deal found 6/1![Frontier logo]()
$187
This Cheapflightsfares deal was found by Cheapflights users on 6/3. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/84:10 pm
DEN
- STL
Nonstop2h 13m
Frontier
Sat 7/118:08 pm
STL
- DEN
Nonstop2h 36m
Frontier
Deal found 6/3![Frontier logo]()
$186
This Cheapflightsfares deal was found by Cheapflights users on 5/29. 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.
Thu 7/94:24 pm
DEN
- PIA
Nonstop2h 10m
Allegiant Air
Sun 7/1211:07 am
PIA
- DEN
Nonstop2h 23m
Allegiant Air
Deal found 5/29![Allegiant Air logo]()
$184
This Frontier deal was found by Cheapflights users on 6/1. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 7/115:05 am
DEN
- ORD
1 stop10h 03m
Frontier
Wed 7/159:57 pm
ORD
- DEN
Nonstop3h 00m
Frontier
Deal found 6/1![Frontier logo]()
$188
This Kiwi.com deal was found by Cheapflights users on 6/3. 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.
Tue 7/146:30 am
DEN
- ORD
1 stop12h 23m
Frontier
Wed 7/221:50 pm
ORD
- DEN
1 stop9h 15m
Frontier
Deal found 6/3![Frontier logo]()
$184
This Cheapflightsfares deal was found by Cheapflights users on 6/3. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/1411:46 pm
DEN
- ORD
1 stop7h 07m
Frontier
Sat 7/189:57 pm
ORD
- DEN
Nonstop3h 00m
Frontier
Deal found 6/3![Frontier logo]()
$187
This Frontier deal was found by Cheapflights users on 6/2. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/154:10 pm
DEN
- STL
Nonstop2h 13m
Frontier
Sat 7/188:08 pm
STL
- DEN
Nonstop2h 36m
Frontier
Deal found 6/2![Frontier logo]()
$183
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 June 4, 2026.
Search for one-way flight options from Denver to Illinois. Find affordable one-way fares based on user searches. Data last updated June 4, 2026.
This Cheapflightsfares deal was found by Cheapflights users on 6/2. 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 10/110:20 am
DEN
- PIA
Nonstop1h 59m
Allegiant Air
Deal found 6/2![Allegiant Air logo]()
$87
This Frontier deal was found by Cheapflights users on 5/30. 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 7/95:05 pm
DEN
- ORD
Nonstop2h 47m
Frontier
Deal found 5/30![Frontier logo]()
$88
This Super.com deal was found by Cheapflights users on 5/30. 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.
Sat 6/205:05 pm
DEN
- ORD
Nonstop2h 38m
Frontier
Deal found 5/30![Frontier logo]()
$91
This Kiwi.com deal was found by Cheapflights users on 5/30. 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.
Fri 7/35:05 pm
DEN
- ORD
Nonstop2h 38m
Frontier
Deal found 5/30![Frontier logo]()
$93
This Kiwi.com deal was found by Cheapflights users on 6/3. 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.
Wed 6/247:43 am
DEN
- RFD
1 stop23h 46m
Multiple Airlines
Deal found 6/3![Multiple Airlines logo]()
$97
This Kiwi.com deal was found by Cheapflights users on 6/2. 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 7/315:05 pm
DEN
- ORD
Nonstop2h 47m
Frontier
Deal found 6/2![Frontier logo]()
$98
This Cheapflightsfares deal was found by Cheapflights users on 5/30. 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 6/135:05 pm
DEN
- ORD
Nonstop2h 38m
Frontier
Deal found 5/30![Frontier logo]()
$99
This Kiwi.com deal was found by Cheapflights users on 6/3. 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 8/66:30 am
DEN
- MDW
1 stop14h 33m
Frontier
Deal found 6/3![Frontier logo]()
$100
This Kiwi.com deal was found by Cheapflights users on 6/3. 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.
Wed 7/87:56 am
DEN
- RFD
1 stop23h 33m
Multiple Airlines
Deal found 6/3![Multiple Airlines logo]()
$101
This Cheapflightsfares deal was found by Cheapflights users on 6/2. 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.
Sat 6/64:54 pm
DEN
- ORD
Nonstop2h 38m
Frontier
Deal found 6/2![Frontier logo]()
$102
This Kiwi.com deal was found by Cheapflights users on 6/3. 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.
Mon 8/3111:42 pm
DEN
- STL
1 stop16h 48m
Frontier
Deal found 6/3![Frontier logo]()
$102
This Kiwi.com deal was found by Cheapflights users on 6/3. 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.
Tue 7/2112:47 pm
DEN
- ORD
1 stop15h 50m
Frontier
Deal found 6/3![Frontier logo]()
$103
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 June 4, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $110 (Booking.com) |
One-way from | $87 (Cheapflightsfares) |
Popular in | March |
Cheapest in | August |
Average price | $259 |
Good round-trip deal | $268 or less |
Good one-way deal | $139 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 June 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
Thu 8/13
8:29 pm-11:59 pm
Nonstop2h 30m
Chicago O'Hare Intl
Tue 8/18
1:30 pm-3:17 pm
Nonstop2h 47m
$227
DenverChicago
DEN - MDW
DENMDW
Denver Intl
Thu 8/6
8:25 pm-11:45 pm
Nonstop2h 20m
Chicago Midway
Wed 8/12
6:40 am-8:10 am
Nonstop2h 30m
$227
DenverChicago
DEN - MDW
DENMDW
Denver Intl
Sat 11/7
6:35 am-9:55 am
Nonstop2h 20m
Chicago Midway
Mon 11/9
5:55 am-7:45 am
Nonstop2h 50m
$237
Quickest round-trip
DenverSt. Louis
DEN - STL
DENSTL
Denver Intl
Wed 8/5
6:35 am-9:35 am
Nonstop2h 00m
Lambert-St Louis
Wed 8/5
6:30 pm-7:45 pm
Nonstop2h 15m
$237
DenverChicago
DEN - ORD
DENORD
Denver Intl
Wed 8/5
9:05 pm-12:44 am
Nonstop2h 39m
Chicago O'Hare Intl
Sun 8/9
5:00 am-6:41 am
Nonstop2h 41m
$241
DenverChicago
DEN - ORD
DENORD
Denver Intl
Wed 9/9
11:15 am-4:48 pm
1 stop4h 33m
Chicago O'Hare Intl
Mon 9/14
5:42 pm-11:25 pm
1 stop6h 43m
$247
DenverChicago
DEN - ORD
DENORD
Denver Intl
Sat 10/10
11:10 am-4:49 pm
1 stop4h 39m
Chicago O'Hare Intl
Tue 10/13
6:00 am-12:03 pm
1 stop7h 03m
$247
DenverChicago
DEN - ORD
DENORD
Denver Intl
Wed 10/7
10:30 am-6:40 pm
1 stop7h 10m
Chicago O'Hare Intl
Sat 10/10
8:55 am-2:03 pm
1 stop6h 08m
$247
DenverSt. Louis
DEN - STL
DENSTL
Denver Intl
Tue 8/11
1:27 pm-4:34 pm
Nonstop2h 07m
Lambert-St Louis
Mon 8/17
5:30 pm-9:44 pm
1 stop5h 14m
$247
DenverChicago
DEN - MDW
DENMDW
Denver Intl
Wed 11/11
6:45 am-12:33 pm
1 stop4h 48m
Chicago Midway
Mon 11/16
9:30 am-2:03 pm
1 stop5h 33m
$247
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-ORD
DEN-MDW
DEN-RFD
DEN-CMI
DEN-STL
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-ORD
DEN-MDW
DEN-RFD
DEN-CMI
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 $227). Flying from Denver to Illinois in December is currently the most expensive (average of $438). 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 June 4, 2026.
It’s optimal to fly from Denver to Illinois in the morning. By choosing this option you can save up to 23% on the cost of your flight, compared to a flight at noon.
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 June 4, 2026.
The most flights from DEN to USIL are scheduled on a Wednesday (71 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (21 on average).
How much does it cost to fly round-trip from Denver to Illinois?
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 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 June 15, 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.
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 June 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.
Comfort
8.0
Food
7.0
Overall
8.0
Entertainment
7.5
Boarding
8.1
Crew
8.6
Reviews
1 / 20
10.0
ExcellentWalter,May 2026
LAS - BUR
Comfort
8.0
Food
7.0
Overall
8.0
Entertainment
7.5
Boarding
8.1
Crew
8.6
Reviews
1 / 20
10.0
ExcellentWalter,May 2026
LAS - BUR
Comfort
8.0
Food
7.0
Overall
8.0
Entertainment
7.5
Boarding
8.1
Crew
8.6
Reviews
1 / 20
10.0
ExcellentWalter,May 2026
LAS - BUR
Comfort
8.0
Food
7.0
Overall
8.0
Entertainment
7.5
Boarding
8.1
Crew
8.6
Reviews
1 / 20
10.0
ExcellentWalter,May 2026
LAS - BUR
Comfort
8.0
Food
7.0
Overall
8.0
Entertainment
7.5
Boarding
8.1
Crew
8.6
Reviews
1 / 20
10.0
ExcellentWalter,May 2026
LAS - BUR
Comfort
8.0
Food
7.0
Overall
8.0
Entertainment
7.5
Boarding
8.1
Crew
8.6
Reviews
1 / 20
10.0
ExcellentWalter,May 2026
LAS - BUR
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 June 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 June 4, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$75 | Average$192 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$84 | Average$169 | FlexibilityNo cancel fee | On-time88% | |
| Cheapest$126 | Average$233 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$157 | Average$291 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$167 | Average$401 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$175 | Average$360 | FlexibilityNo cancel fee | On-time69% |