$27+ Cheap flights from Illinois to Denver (DEN)
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 5/26. Fares are subject to change and may not be available on all flights or dates of travel.
ORD — DEN
May 31 — Jun 71
Round-trip
1 adult, Economy
We work with more than 300 partners to bring you better travel deals
Find cheap flights from Illinois to Denver with Cheapflights
1. Tell us where you want to go
Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”2. Select your favorite providers
We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.3. Compare prices and book
Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.Cheap flight deals from Illinois to Denver
Cheapest
Best
Last-minute
One-way
Cheapest flights from Illinois to DenverExplore the most affordable flight options available from Illinois to Denver. Find the lowest fares from popular airlines and budget airlines, with prices last updated on May 1, 2026.
Explore the most affordable flight options available from Illinois to Denver. Find the lowest fares from popular airlines and budget airlines, with prices last updated on May 1, 2026.
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 8/218:08 pm
STL
- DEN
Nonstop2h 36m
Frontier
Tue 8/254:12 pm
DEN
- STL
Nonstop2h 11m
Frontier
Deal found 4/30![Frontier logo]()
$101
This Frontier 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 6/18:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Wed 6/104:12 pm
DEN
- STL
Nonstop2h 11m
Frontier
Deal found 4/28![Frontier logo]()
$102
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 5/206:51 pm
STL
- DEN
1 stop9h 34m
Frontier
Wed 5/274:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Deal found 4/29![Frontier logo]()
$106
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.
Sat 5/238:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Wed 5/274:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Deal found 4/30![Frontier logo]()
$107
This Frontier 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 6/228:08 pm
STL
- DEN
Nonstop2h 36m
Frontier
Sat 6/274:12 pm
DEN
- STL
Nonstop2h 11m
Frontier
Deal found 4/28![Frontier logo]()
$108
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.
Tue 5/268:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Thu 5/284:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Deal found 4/29![Frontier logo]()
$110
This Kiwi.com 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 5/268:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Tue 6/211:54 pm
DEN
- STL
1 stop8h 01m
Frontier
Deal found 4/28![Frontier logo]()
$113
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.
Mon 5/258:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Wed 5/274:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Deal found 4/29![Frontier logo]()
$116
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.
Wed 5/276:51 pm
STL
- DEN
1 stop15h 47m
Frontier
Wed 6/34:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Deal found 4/29![Frontier logo]()
$117
This Frontier 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 6/59:06 pm
STL
- DEN
1 stop13h 32m
Frontier
Tue 6/94:12 pm
DEN
- STL
Nonstop2h 11m
Frontier
Deal found 4/30![Frontier logo]()
$118
This Kiwi.com 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/107:04 pm
STL
- DEN
1 stop28h 57m
Frontier
Wed 6/174:12 pm
DEN
- STL
Nonstop2h 11m
Frontier
Deal found 4/28![Frontier logo]()
$119
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 5/248:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Wed 5/274:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Deal found 4/29![Frontier logo]()
$120
Best flights from Illinois to DenverDiscover carefully curated flight deals from Illinois to Denver that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated May 1, 2026.
Discover carefully curated flight deals from Illinois to Denver that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated May 1, 2026.
This Kiwi.com deal was found by Cheapflights users on 4/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/244:17 pm
STL
- DEN
1 stop7h 47m
Frontier
Mon 6/294:12 pm
DEN
- STL
Nonstop2h 11m
Frontier
Deal found 4/25![Frontier logo]()
$172
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.
Wed 6/38:50 pm
MDW
- DEN
Nonstop2h 45m
Southwest
Wed 6/108:05 am
DEN
- MDW
1 stop4h 45m
Southwest
Deal found 4/28![Southwest logo]()
$221
This Delta deal was found by Cheapflights users on 4/27. Clicking the “Pick Dates” 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 5/209:22 am
MDW
- DEN
1 stop5h 37m
Delta
Thu 5/216:00 am
DEN
- MDW
1 stop6h 19m
Delta
Deal found 4/27![Delta logo]()
$231
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.
Wed 6/245:00 am
ORD
- DEN
Nonstop2h 41m
United Airlines
Sun 6/289:05 pm
DEN
- ORD
Nonstop2h 39m
United Airlines
Deal found 4/29![United Airlines logo]()
$233
This American Airlines 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 6/236:43 pm
CMI
- DEN
1 stop6h 34m
American Airlines
Sat 6/276:22 am
DEN
- CMI
1 stop6h 53m
American Airlines
Deal found 4/28![American Airlines logo]()
$270
This Kiwi.com 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 5/137:31 pm
SPI
- DEN
1 stop13h 53m
Multiple Airlines
Wed 5/205:05 am
DEN
- SPI
2 stops12h 46m
Multiple Airlines
Deal found 4/28![Multiple Airlines logo]()
$426
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 5/273:45 pm
ORD
- DEN
1 stop6h 10m
Southwest
Wed 6/311:25 am
DEN
- ORD
Nonstop2h 35m
Southwest
Deal found 4/29![Southwest logo]()
$221
This Delta deal was found by Cheapflights users on 4/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 6/155:30 am
ORD
- DEN
1 stop8h 29m
Delta
Wed 6/1710:25 am
DEN
- ORD
1 stop5h 01m
Delta
Deal found 4/25![Delta logo]()
$253
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.
Thu 6/115:15 am
MDW
- DEN
Nonstop2h 35m
Southwest
Tue 6/236:15 am
DEN
- MDW
Nonstop2h 25m
Southwest
Deal found 4/29![Southwest logo]()
$233
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.
Fri 6/56:00 am
ORD
- DEN
Nonstop2h 42m
United Airlines
Sun 6/79:05 pm
DEN
- ORD
Nonstop2h 39m
United Airlines
Deal found 4/29![United Airlines logo]()
$265
This United Airlines deal was found by Cheapflights users on 4/27. Clicking the “Pick Dates” 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 6/255:00 am
ORD
- DEN
Nonstop2h 42m
United Airlines
Mon 6/296:00 pm
DEN
- ORD
Nonstop2h 39m
United Airlines
Deal found 4/27![United Airlines logo]()
$265
This Delta 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/217:01 pm
STL
- DEN
1 stop6h 32m
Delta
Mon 5/2512:56 am
DEN
- STL
1 stop6h 22m
Delta
Deal found 4/28![Delta logo]()
$275
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 7/229:05 pm
MDW
- DEN
Nonstop2h 45m
Southwest
Sun 7/265:50 am
DEN
- MDW
Nonstop2h 25m
Southwest
Deal found 4/29![Southwest logo]()
$255
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.
Tue 9/229:49 am
CMI
- DEN
1 stop6h 28m
United Airlines
Tue 9/295:42 pm
DEN
- CMI
1 stop5h 23m
United Airlines
Deal found 4/29![United Airlines logo]()
$270
This American Airlines deal was found by Cheapflights users on 4/27. Clicking the “Pick Dates” 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.
Tue 5/126:55 pm
CMI
- DEN
1 stop4h 50m
American Airlines
Sat 5/166:19 am
DEN
- CMI
1 stop6h 28m
American Airlines
Deal found 4/27![American Airlines logo]()
$328
This Delta 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 7/65:57 pm
ORD
- DEN
1 stop6h 39m
Delta
Wed 7/87:15 am
DEN
- ORD
1 stop5h 59m
Delta
Deal found 4/28![Delta logo]()
$275
This Southwest deal was found by Cheapflights users on 4/27. Clicking the “Pick Dates” 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 6/16:00 am
MDW
- DEN
Nonstop2h 40m
Southwest
Sat 6/1312:05 pm
DEN
- MDW
1 stop3h 55m
Southwest
Deal found 4/27![Southwest logo]()
$259
This American Airlines 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 5/133:01 pm
CMI
- DEN
1 stop5h 54m
American Airlines
Sun 5/175:30 am
DEN
- CMI
1 stop8h 01m
American Airlines
Deal found 4/28![American Airlines logo]()
$328
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.
Fri 7/175:54 pm
ORD
- DEN
1 stop6h 33m
Delta
Wed 7/222:10 pm
DEN
- ORD
1 stop6h 58m
Delta
Deal found 4/29![Delta logo]()
$275
This United Airlines deal was found by Cheapflights users on 4/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/36:00 am
ORD
- DEN
Nonstop2h 42m
United Airlines
Wed 6/36:00 pm
DEN
- ORD
Nonstop2h 39m
United Airlines
Deal found 4/25![United Airlines logo]()
$281
This Southwest deal was found by Cheapflights users on 4/27. Clicking the “Pick Dates” 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 5/266:40 pm
STL
- DEN
1 stop5h 00m
Southwest
Wed 5/278:40 am
DEN
- STL
1 stop4h 50m
Southwest
Deal found 4/27![Southwest logo]()
$261
This Delta deal was found by Cheapflights users on 4/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/175:57 pm
ORD
- DEN
1 stop6h 34m
Delta
Sun 6/215:45 am
DEN
- ORD
1 stop7h 44m
Delta
Deal found 4/25![Delta logo]()
$280
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.
Sun 7/197:34 pm
CMI
- DEN
1 stop6h 24m
United Airlines
Sat 7/254:40 pm
DEN
- CMI
1 stop5h 00m
United Airlines
Deal found 4/29![United Airlines logo]()
$284
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.
Sat 6/278:30 pm
MDW
- DEN
Nonstop2h 45m
Southwest
Thu 7/28:50 pm
DEN
- MDW
Nonstop2h 20m
Southwest
Deal found 4/30![Southwest logo]()
$265
This Delta deal was found by Cheapflights users on 4/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 5/318:05 pm
ORD
- DEN
1 stop4h 36m
Delta
Mon 6/1512:11 pm
DEN
- ORD
1 stop6h 20m
Delta
Deal found 4/25![Delta logo]()
$285
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 7/238:20 pm
PIA
- DEN
1 stop5h 39m
United Airlines
Tue 7/286:00 am
DEN
- PIA
1 stop5h 46m
United Airlines
Deal found 4/30![United Airlines logo]()
$289
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.
Fri 7/35:15 am
MDW
- DEN
Nonstop2h 35m
Southwest
Sat 7/115:15 am
DEN
- MDW
Nonstop2h 20m
Southwest
Deal found 4/28![Southwest logo]()
$265
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 5/274:29 pm
EVV
- DEN
1 stop16h 55m
Multiple Airlines
Sat 5/305:38 pm
DEN
- EVV
2 stops37h 01m
Multiple Airlines
Deal found 4/29![Multiple Airlines logo]()
$482
This American Airlines 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/286:39 pm
CMI
- DEN
1 stop6h 20m
American Airlines
Sun 5/316:22 am
DEN
- CMI
1 stop6h 53m
American Airlines
Deal found 4/28![American Airlines logo]()
$404
This Delta deal was found by Cheapflights users on 4/26. Clicking the “Pick Dates” 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 10/35:00 pm
MLI
- DEN
1 stop7h 45m
Delta
Fri 10/912:59 am
DEN
- MLI
1 stop8h 27m
Delta
Deal found 4/26![Delta logo]()
$289
Last-minute flights from Illinois to DenverDiscover last-minute flight deals from Illinois to Denver. Data last updated May 1, 2026 and is based on user searches.
Discover last-minute flight deals from Illinois to Denver. Data last updated May 1, 2026 and is based on user searches.
This Frontier 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/88:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Sat 5/164:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Deal found 4/28![Frontier logo]()
$128
This Frontier deal was found by Cheapflights users on 4/26. Clicking the “Pick Dates” 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 5/141:59 pm
ORD
- DEN
1 stop9h 25m
Frontier
Tue 5/194:54 pm
DEN
- ORD
Nonstop2h 38m
Frontier
Deal found 4/26![Frontier logo]()
$164
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 5/206:51 pm
STL
- DEN
1 stop9h 34m
Frontier
Wed 5/274:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Deal found 4/29![Frontier logo]()
$106
This Super.com deal was found by Cheapflights users on 4/26. Clicking the “Pick Dates” 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 5/229:37 pm
ORD
- DEN
Nonstop3h 07m
Frontier
Fri 5/294:54 pm
DEN
- ORD
Nonstop2h 38m
Frontier
Deal found 4/26![Frontier logo]()
$165
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.
Sat 5/238:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Wed 5/274:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Deal found 4/30![Frontier logo]()
$107
This Frontier deal was found by Cheapflights users on 4/27. Clicking the “Pick Dates” 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 5/236:30 pm
STL
- DEN
1 stop6h 39m
Frontier
Sat 5/304:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Deal found 4/27![Frontier logo]()
$124
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.
Sat 5/236:30 pm
STL
- DEN
1 stop6h 39m
Frontier
Tue 5/264:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Deal found 4/30![Frontier logo]()
$133
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 5/248:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Wed 5/274:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Deal found 4/29![Frontier logo]()
$120
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.
Mon 5/258:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Wed 5/274:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Deal found 4/29![Frontier logo]()
$116
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.
Tue 5/268:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Thu 5/284:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Deal found 4/29![Frontier logo]()
$110
This Kiwi.com 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 5/268:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Tue 6/211:54 pm
DEN
- STL
1 stop8h 01m
Frontier
Deal found 4/28![Frontier logo]()
$113
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.
Wed 5/276:51 pm
STL
- DEN
1 stop15h 47m
Frontier
Wed 6/34:15 pm
DEN
- STL
Nonstop2h 08m
Frontier
Deal found 4/29![Frontier logo]()
$117
One-way flights from Illinois to DenverSearch for one-way flight options from Illinois to Denver. Find affordable one-way fares based on user searches. Data last updated May 1, 2026.
Search for one-way flight options from Illinois to Denver. Find affordable one-way fares based on user searches. Data last updated May 1, 2026.
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 5/268:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 4/30![Frontier logo]()
$27
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 6/238:08 pm
STL
- DEN
Nonstop2h 36m
Frontier
Deal found 4/30![Frontier logo]()
$28
This Frontier 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 6/228:08 pm
STL
- DEN
Nonstop2h 36m
Frontier
Deal found 4/28![Frontier logo]()
$54
This Cheapflightsfares deal was found by Cheapflights users on 4/27. Clicking the “Pick Dates” 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 8/3010:07 am
PIA
- DEN
Nonstop2h 19m
Allegiant Air
Deal found 4/27![Allegiant Air logo]()
$58
This eDestinos deal was found by Cheapflights users on 4/26. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure eDestinos is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/158:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 4/26![Frontier logo]()
$69
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.
Wed 5/206:51 pm
STL
- DEN
1 stop9h 34m
Frontier
Deal found 4/29![Frontier logo]()
$70
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.
Thu 5/288:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 4/30![Frontier logo]()
$73
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 8/218:08 pm
STL
- DEN
Nonstop2h 36m
Frontier
Deal found 4/30![Frontier logo]()
$74
This Super.com deal was found by Cheapflights users on 4/27. Clicking the “Pick Dates” 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 5/184:19 pm
STL
- DEN
1 stop17h 05m
Frontier
Deal found 4/27![Frontier logo]()
$75
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.
Mon 5/258:08 pm
STL
- DEN
Nonstop2h 33m
Frontier
Deal found 4/30![Frontier logo]()
$79
This Trip.com deal was found by Cheapflights users on 4/27. Clicking the “Pick Dates” 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.
Tue 5/126:00 am
MDW
- DEN
1 stop9h 04m
Frontier
Deal found 4/27![Frontier logo]()
$92
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 6/312:04 pm
MDW
- DEN
1 stop11h 20m
Frontier
Deal found 4/29![Frontier logo]()
$93
Find flight deals from Illinois to Denver
Keep the following information in mind while searching for Illinois to Denver flight deals. Data was last updated May 1, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $101 (Cheapflightsfares) |
One-way from | $27 (Kiwi.com) |
Popular in | March |
Cheapest in | September |
Average price | $228 |
Good round-trip deal | $224 or less |
Good one-way deal | $133 or less |
Cheapflights Fare Finder
Customize your flight search to find flights from Illinois to Denver 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 1, 2026.
Use the filters below to find and compare flights from Illinois to Denver that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
St. LouisDenver
STL - DEN
STLDEN
Lambert-St Louis
Wed 6/24
4:17 pm-11:04 pm
1 stop7h 47m
Denver Intl
Mon 6/29
4:12 pm-7:23 pm
Nonstop2h 11m
$172
ChicagoDenver
MDW - DEN
MDWDEN
Chicago Midway
Wed 6/3
8:50 pm-10:35 pm
Nonstop2h 45m
Denver Intl
Wed 6/10
8:05 am-1:50 pm
1 stop4h 45m
$221
ChicagoDenver
ORD - DEN
ORDDEN
Chicago O'Hare Intl
Wed 5/27
3:45 pm-8:55 pm
1 stop6h 10m
Denver Intl
Wed 6/3
11:25 am-3:00 pm
Nonstop2h 35m
$221
ChicagoDenver
MDW - DEN
MDWDEN
Chicago Midway
Wed 5/20
9:22 am-1:59 pm
1 stop5h 37m
Denver Intl
Thu 5/21
6:00 am-1:19 pm
1 stop6h 19m
$231
ChicagoDenver
ORD - DEN
ORDDEN
Chicago O'Hare Intl
Wed 6/24
5:00 am-6:41 am
Nonstop2h 41m
Denver Intl
Sun 6/28
9:05 pm-12:44 am
Nonstop2h 39m
$233
ChicagoDenver
MDW - DEN
MDWDEN
Chicago Midway
Thu 6/11
5:15 am-6:50 am
Nonstop2h 35m
Denver Intl
Tue 6/23
6:15 am-9:40 am
Nonstop2h 25m
$233
ChicagoDenver
ORD - DEN
ORDDEN
Chicago O'Hare Intl
Mon 6/15
5:30 am-12:59 pm
1 stop8h 29m
Denver Intl
Wed 6/17
10:25 am-4:26 pm
1 stop5h 01m
$253
ChicagoDenver
MDW - DEN
MDWDEN
Chicago Midway
Wed 7/22
9:05 pm-10:50 pm
Nonstop2h 45m
Denver Intl
Sun 7/26
5:50 am-9:15 am
Nonstop2h 25m
$255
ChicagoDenver
MDW - DEN
MDWDEN
Chicago Midway
Mon 6/1
6:00 am-7:40 am
Nonstop2h 40m
Denver Intl
Sat 6/13
12:05 pm-5:00 pm
1 stop3h 55m
$259
St. LouisDenver
STL - DEN
STLDEN
Lambert-St Louis
Tue 5/26
6:40 pm-10:40 pm
1 stop5h 00m
Denver Intl
Wed 5/27
8:40 am-2:30 pm
1 stop4h 50m
$261
Showing 1-10 of 60 resultsSorted by cheapest first
Best time to book a flight from Illinois to Denver
Have a flexible travel schedule? Discover the best time to fly to Denver from Illinois with our price prediction graph.
STL-DEN
MDW-DEN
ORD-DEN
PIA-DEN
MLI-DEN
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 Illinois to Denver
USIL-DEN
STL-DEN
MDW-DEN
ORD-DEN
PIA-DEN
How far ahead should I book a flight from Illinois to Denver?
To ensure you get the cheapest price possible for a flight from Illinois to Denver, you should look to book at least 84 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 Illinois to Denver?
Currently, October is the cheapest month in which you can book a flight from Illinois to Denver (average of $168). Flying from Illinois to Denver in March is currently the most expensive (average of $349). 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 IL to DEN?
Find hourly flight availability from Illinois to Denver. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated May 1, 2026.
A simple way to save on the total cost of your ticket is to fly from Illinois to Denver in the evening. If you’re flexible enough to do this you can expect to save up to 28% on your trip compared to booking a flight in the morning.
What is the cheapest day to fly from Illinois to Denver?
Use this chart to determine the cheapest time to fly round-trip from Illinois to Denver. Price data was last updated on May 18, 2025.
Travelers seeking maximum savings on their Illinois to Denver flight should consider departing on Saturday afternoons when fares are most often at their lowest. Monday mornings flights should be avoided if possible as fares are typically the most expensive at this time.
Weekly flight availability from Illinois to Denver
Explore weekly flight availability from Illinois to Denver. 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 1, 2026.
The most flights from USIL to DEN are scheduled on a Thursday (64 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (37 on average).
How much does it cost to fly round-trip from Illinois to Denver?
Related info for your journey
Find useful and relevant information for your journey from Illinois to Denver. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
Traveling to a place near Denver?
Book flights to Denver if you plan to visit one of these locationsThornton
Black Hawk
Lakewood
Westminster
Broomfield
Golden
Centennial
Greeley
Lone Tree
Wheat Ridge
Silverthorne
Central City
Cripple Creek
Winter Park
Manitou Springs
Frisco
Englewood
Fort Morgan
Glendale
Evergreen
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.
Alternative routes
Complete your trip
Denver flight routes
Flights by cabin class
Other flight options
Popular flights
Top destinations
Alternative routes for Illinois to Denver
See prices for flight routes from nearby airports that may be better suited for you.
Complete your trip
Complete your trip to Denver by adding a car rental and/or hotel reservation to your travel itinerary.
Other flights to Denver
Explore flights to Denver departing from other origins. Flights are based on user searches made on Cheapflights and were last updated on May 1, 2026.
Search flights from Illinois to Denver by cabin class
Find flights from Illinois to Denver, based on your preferred cabin class, be it economy, premium economy, business, or first class.
Illinois and Denver flights
Browse other Illinois and Denver flight options. Last updated on May 1, 2026.
Popular flight searches
Check out other popular destinations found by fellow travelers in 2026
Illinois to Denver flights
Consider these flights traveling from Illinois to Denver.
Top 6 airlines flying from Illinois to Denver
Discover the top 6 airlines that operate flights from Illinois to Denver. 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 1, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$53 | Average$168 | FlexibilityNo cancel fee | On-time88% | |
| Cheapest$68 | Average$167 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$145 | Average$223 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$151 | Average$269 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$152 | Average$374 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$160 | Average$365 | FlexibilityNo cancel fee | On-time69% |