$44+ Cheap flights from Colorado to Illinois
This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 11/9. Fares are subject to change and may not be available on all flights or dates of travel.
DEN — ORD
Oct 14 — Oct 211
Round-trip
1 adult, Economy
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Find cheap flights from Colorado to Illinois 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
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Cheapest flights from Colorado to IllinoisExplore the most affordable flight options available from Colorado to Illinois. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 14, 2026.
Explore the most affordable flight options available from Colorado to Illinois. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 14, 2026.
This Cheapflightsfares deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/2910:20 am -
Nonstop1h 59m
Sun 11/15:24 pm -
Nonstop2h 20m
Deal found 9/10![Allegiant Air logo]()
$119
This Cheapflightsfares deal was found by Cheapflights users on 9/12. Clicking the “Pick Dates” 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 11/138:55 pm -
Nonstop2h 26m
Mon 11/166:30 am -
Nonstop2h 56m
Deal found 9/12![Frontier logo]()
$121
This Cheapflightsfares deal was found by Cheapflights users on 9/12. Clicking the “Pick Dates” 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 10/24:12 pm -
Nonstop2h 05m
Mon 10/58:10 pm -
Nonstop2h 29m
Deal found 9/12![Frontier logo]()
$122
This Booking.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” 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.
Fri 10/210:49 pm -
1 stop11h 43m
Sat 10/38:10 pm -
Nonstop2h 29m
Deal found 9/11![Frontier logo]()
$136
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” 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 10/206:57 pm -
1 stop21h 43m
Fri 10/238:00 pm -
Nonstop2h 39m
Deal found 9/11![Frontier logo]()
$140
This Kiwi.com deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” 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 11/1812:21 pm -
Nonstop2h 02m
Tue 12/16:05 pm -
1 stop15h 18m
Deal found 9/10![Frontier logo]()
$141
This Super.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” 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 10/194:12 pm -
Nonstop2h 03m
Fri 10/238:00 pm -
Nonstop2h 39m
Deal found 9/11![Frontier logo]()
$144
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” 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 10/17:12 pm -
1 stop20h 22m
Sat 10/38:10 pm -
Nonstop2h 29m
Deal found 9/11![Frontier logo]()
$145
This Kiwi.com deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” 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 10/276:31 pm -
1 stop22h 09m
Fri 10/306:44 pm -
1 stop14h 38m
Deal found 9/14![Frontier logo]()
$146
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” 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 10/234:12 pm -
Nonstop2h 03m
Mon 10/266:35 pm -
1 stop14h 47m
Deal found 9/11![Frontier logo]()
$148
This Kiwi.com deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” 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 11/164:09 pm -
Nonstop2h 05m
Tue 12/16:05 pm -
1 stop15h 18m
Deal found 9/10![Frontier logo]()
$152
This Priceline deal was found by Cheapflights users on 9/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/74:09 pm -
Nonstop2h 05m
Mon 11/97:59 pm -
Nonstop2h 31m
Deal found 9/13![Frontier logo]()
$154
Best flights from Colorado to IllinoisDiscover carefully curated flight deals from Colorado to Illinois that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated September 14, 2026.
Discover carefully curated flight deals from Colorado to Illinois that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated September 14, 2026.
This Southwest deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” 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 10/272:20 pm -
1 stop4h 25m
Thu 10/296:05 am -
Nonstop2h 40m
Deal found 9/14![Southwest logo]()
$215
This Delta deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” 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 2/171:40 pm -
1 stop7h 40m
Sat 2/207:10 am -
1 stop6h 48m
Deal found 9/14![Delta logo]()
$265
This United Airlines deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/249:35 am -
Nonstop2h 40m
Sat 10/2410:00 pm -
Nonstop2h 54m
Deal found 9/11![United Airlines logo]()
$277
This Kiwi.com deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” 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 10/2910:37 pm -
1 stop11h 50m
Sun 11/18:53 pm -
1 stop27h 56m
Deal found 9/10![Multiple Airlines logo]()
$277
This American Airlines deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” 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 10/316:00 am -
1 stop5h 59m
Fri 11/64:53 pm -
1 stop6h 13m
Deal found 9/10![American Airlines logo]()
$343
This Southwest deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/15:50 am -
Nonstop2h 20m
Sat 10/35:05 pm -
Nonstop2h 40m
Deal found 9/10![Southwest logo]()
$229
This Southwest deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/228:55 pm -
Nonstop2h 25m
Sat 10/245:05 pm -
Nonstop2h 40m
Deal found 9/10![Southwest logo]()
$229
This Alaska Airlines deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 12/41:54 pm -
1 stop25h 53m
Tue 12/83:19 pm -
2 stops22h 37m
Deal found 9/14![Alaska Airlines logo]()
$528
This Delta deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” 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 2/201:40 pm -
1 stop7h 40m
Tue 2/235:30 am -
1 stop8h 28m
Deal found 9/14![Delta logo]()
$265
This Kiwi.com deal was found by Cheapflights users on 9/9. Clicking the “Pick Dates” 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 10/2210:44 pm -
1 stop11h 43m
Sun 10/258:53 pm -
1 stop23h 57m
Deal found 9/9![Multiple Airlines logo]()
$303
This Delta deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/106:15 am -
1 stop6h 44m
Sun 12/136:20 am -
1 stop7h 01m
Deal found 9/14![Delta logo]()
$285
This United Airlines deal was found by Cheapflights users on 9/13. Clicking the “Pick Dates” 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 12/315:49 pm -
Nonstop2h 21m
Mon 1/42:35 pm -
1 stop6h 05m
Deal found 9/13![United Airlines logo]()
$329
This Southwest deal was found by Cheapflights users on 9/9. Clicking the “Pick Dates” 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 11/56:30 pm -
1 stop5h 35m
Sun 11/85:55 am -
Nonstop2h 50m
Deal found 9/9![Southwest logo]()
$272
This Kiwi.com deal was found by Cheapflights users on 9/12. Clicking the “Pick Dates” 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 11/1210:37 pm -
1 stop10h 56m
Sun 11/158:37 pm -
1 stop28h 12m
Deal found 9/12![Multiple Airlines logo]()
$307
This American Airlines deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” 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 10/303:14 pm -
2 stops7h 57m
Sun 11/15:03 pm -
1 stop6h 51m
Deal found 9/14![American Airlines logo]()
$344
This Delta deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” 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 10/3011:07 am -
1 stop4h 40m
Sun 11/19:29 am -
1 stop6h 38m
Deal found 9/10![Delta logo]()
$296
This United Airlines deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” 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 10/288:09 am -
Nonstop2h 50m
Sun 11/17:00 am -
1 stop4h 53m
Deal found 9/14![United Airlines logo]()
$333
This Southwest deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/227:10 am -
Nonstop2h 00m
Thu 10/229:50 pm -
Nonstop2h 25m
Deal found 9/11![Southwest logo]()
$277
This Kiwi.com deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” 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 11/510:37 pm -
1 stop10h 56m
Sun 11/88:37 pm -
1 stop14h 11m
Deal found 9/10![Multiple Airlines logo]()
$315
This United Airlines deal was found by Cheapflights users on 9/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/241:37 pm -
1 stop5h 43m
Sat 10/316:59 am -
1 stop6h 34m
Deal found 9/13![United Airlines logo]()
$334
This Delta deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” 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 11/76:00 am -
1 stop8h 17m
Tue 11/101:05 pm -
1 stop8h 45m
Deal found 9/10![Delta logo]()
$313
This Southwest deal was found by Cheapflights users on 9/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/224:20 pm -
1 stop4h 40m
Sun 10/257:45 am -
1 stop4h 05m
Deal found 9/9![Southwest logo]()
$287
This United Airlines deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” 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 2/175:13 pm -
1 stop4h 31m
Sat 2/207:45 pm -
Nonstop2h 58m
Deal found 9/14![United Airlines logo]()
$335
This Southwest deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/2110:45 am -
2 stops5h 05m
Thu 10/222:10 pm -
1 stop4h 35m
Deal found 9/14![Southwest logo]()
$298
This Delta deal was found by Cheapflights users on 9/13. Clicking the “Pick Dates” 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 11/1310:36 am -
1 stop6h 54m
Sun 11/158:29 am -
1 stop7h 40m
Deal found 9/13![Delta logo]()
$335
This United Airlines deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/161:30 pm -
Nonstop2h 07m
Tue 10/209:00 am -
Nonstop2h 30m
Deal found 9/11![United Airlines logo]()
$357
This Alaska Airlines deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/28:08 am -
2 stops14h 51m
Sat 10/38:10 am -
2 stops15h 27m
Deal found 9/10![Alaska Airlines logo]()
$533
This Southwest deal was found by Cheapflights users on 9/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/228:45 pm -
Nonstop2h 05m
Mon 10/266:05 am -
Nonstop2h 20m
Deal found 9/13![Southwest logo]()
$301
This Kiwi.com deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” 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 10/110:47 pm -
1 stop11h 40m
Sun 10/49:36 pm -
1 stop13h 31m
Deal found 9/10![Multiple Airlines logo]()
$403
This Delta deal was found by Cheapflights users on 9/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/57:00 am -
1 stop8h 29m
Sun 11/85:09 pm -
1 stop7h 03m
Deal found 9/13![Delta logo]()
$339
Last-minute flights from Colorado to IllinoisDiscover last-minute flight deals from Colorado to Illinois. Data last updated September 14, 2026 and is based on user searches.
Discover last-minute flight deals from Colorado to Illinois. Data last updated September 14, 2026 and is based on user searches.
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” 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 10/17:12 pm -
1 stop20h 22m
Sat 10/38:10 pm -
Nonstop2h 29m
Deal found 9/11![Frontier logo]()
$145
This Super.com deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” 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 10/17:12 pm -
1 stop20h 22m
Wed 10/712:17 pm -
1 stop7h 16m
Deal found 9/10![Frontier logo]()
$164
This Cheapflightsfares deal was found by Cheapflights users on 9/12. Clicking the “Pick Dates” 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 10/24:12 pm -
Nonstop2h 05m
Mon 10/58:10 pm -
Nonstop2h 29m
Deal found 9/12![Frontier logo]()
$122
This Booking.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” 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.
Fri 10/210:49 pm -
1 stop11h 43m
Sat 10/38:10 pm -
Nonstop2h 29m
Deal found 9/11![Frontier logo]()
$136
This Cheapflightsfares deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” 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 10/37:12 pm -
1 stop20h 22m
Mon 10/58:10 pm -
Nonstop2h 29m
Deal found 9/11![Frontier logo]()
$157
This Frontier deal was found by Cheapflights users on 9/12. Clicking the “Pick Dates” 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 10/164:12 pm -
Nonstop2h 03m
Sat 10/247:42 pm -
Nonstop2h 27m
Deal found 9/12![Frontier logo]()
$160
This Super.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” 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 10/194:12 pm -
Nonstop2h 03m
Fri 10/238:00 pm -
Nonstop2h 39m
Deal found 9/11![Frontier logo]()
$144
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” 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 10/206:57 pm -
1 stop21h 43m
Fri 10/238:00 pm -
Nonstop2h 39m
Deal found 9/11![Frontier logo]()
$140
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” 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 10/234:12 pm -
Nonstop2h 03m
Mon 10/266:35 pm -
1 stop14h 47m
Deal found 9/11![Frontier logo]()
$148
This Kiwi.com deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” 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 10/268:55 pm -
Nonstop2h 29m
Fri 10/306:30 am -
Nonstop2h 56m
Deal found 9/14![Frontier logo]()
$170
This Kiwi.com deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” 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 10/276:31 pm -
1 stop22h 09m
Fri 10/306:44 pm -
1 stop14h 38m
Deal found 9/14![Frontier logo]()
$146
This Cheapflightsfares deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/2910:20 am -
Nonstop1h 59m
Sun 11/15:24 pm -
Nonstop2h 20m
Deal found 9/10![Allegiant Air logo]()
$119
One-way flights from Colorado to IllinoisSearch for one-way flight options from Colorado to Illinois. Find affordable one-way fares based on user searches. Data last updated September 14, 2026.
Search for one-way flight options from Colorado to Illinois. Find affordable one-way fares based on user searches. Data last updated September 14, 2026.
This Super.com deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” 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 11/94:09 pm -
Nonstop2h 05m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/10![Frontier logo]()
$44
This Booking.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” 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.
Mon 10/264:12 pm -
Nonstop2h 03m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/11![Frontier logo]()
$45
This Frontier deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” 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 10/74:12 pm -
Nonstop2h 05m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/10![Frontier logo]()
$54
This Super.com deal was found by Cheapflights users on 9/12. Clicking the “Pick Dates” 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 12/113:50 pm -
Nonstop2h 04m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/12![Frontier logo]()
$60
This Super.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” 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 11/134:09 pm -
Nonstop2h 05m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/11![Frontier logo]()
$61
This Super.com deal was found by Cheapflights users on 9/13. Clicking the “Pick Dates” 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 10/2110:38 am -
1 stop6h 02m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/13![Frontier logo]()
$67
This FlightHub deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/16:24 pm -
1 stop11h 45m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/14![Frontier logo]()
$68
This Super.com deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” 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 10/1412:21 pm -
Nonstop2h 03m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/10![Frontier logo]()
$70
This Frontier deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” 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 10/24:12 pm -
Nonstop2h 05m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/10![Frontier logo]()
$71
This Kiwi.com deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” 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 10/276:31 pm -
1 stop22h 09m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/14![Frontier logo]()
$72
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” 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 11/237:55 am -
Nonstop2h 08m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/11![Frontier logo]()
$76
This Super.com deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” 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 10/56:40 am -
1 stop8h 54m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/10![Frontier logo]()
$77
Find flight deals from Colorado to Illinois
Keep the following information in mind while searching for Colorado to Illinois flight deals. Data was last updated September 14, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $119 (Cheapflightsfares) |
One-way from | $44 (Super.com) |
Popular in | July |
Cheapest in | January |
Average price | $278 |
Good round-trip deal | $158 or less |
Good one-way deal | $145 or less |
Cheapflights Fare Finder
Customize your flight search to find flights from Colorado to Illinois that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 7,457,451 searches. Data last updated September 14, 2026.
Use the filters below to find and compare flights from Colorado to Illinois that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
Quickest round-trip
DenverSt. Louis
DEN Denver Intl - STL Lambert-St Louis
DENSTL
Denver Intl
Thu 10/8
5:50 am-8:50 am
Nonstop2h 00m
Lambert-St Louis
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$89
DenverSt. Louis
DEN Denver Intl - STL Lambert-St Louis
DENSTL
Denver Intl
Wed 12/9
5:35 am-1:36 pm
1 stop7h 01m
Lambert-St Louis
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$99
DenverChicago
DEN Denver Intl - MDW Chicago Midway
DENMDW
Denver Intl
Sat 10/17
6:55 am-12:05 pm
1 stop4h 10m
Chicago Midway
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$111
DenverChicago
DEN Denver Intl - MDW Chicago Midway
DENMDW
Denver Intl
Thu 10/15
5:55 pm-9:15 pm
Nonstop2h 20m
Chicago Midway
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$115
DenverChicago
DEN Denver Intl - MDW Chicago Midway
DENMDW
Denver Intl
Mon 10/26
5:55 pm-9:15 pm
Nonstop2h 20m
Chicago Midway
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$115
DenverChicago
DEN Denver Intl - MDW Chicago Midway
DENMDW
Denver Intl
Thu 11/12
6:45 pm-10:00 pm
Nonstop2h 15m
Chicago Midway
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$115
DenverChicago
DEN Denver Intl - MDW Chicago Midway
DENMDW
Denver Intl
Wed 10/7
7:50 pm-11:15 pm
Nonstop2h 25m
Chicago Midway
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$115
DenverSt. Louis
DEN Denver Intl - STL Lambert-St Louis
DENSTL
Denver Intl
Sat 10/17
4:38 pm-10:58 pm
1 stop5h 20m
Lambert-St Louis
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$124
DenverChicago
DEN Denver Intl - MDW Chicago Midway
DENMDW
Denver Intl
Fri 10/16
12:59 am-9:32 am
1 stop7h 33m
Chicago Midway
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$125
DenverChicago
DEN Denver Intl - MDW Chicago Midway
DENMDW
Denver Intl
Fri 11/27
8:40 pm-11:55 pm
Nonstop2h 15m
Chicago Midway
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$129
Showing 1-10 of 60 resultsSorted by cheapest first
Best time to book a flight from Colorado to Illinois
Have a flexible travel schedule? Discover the best time to fly to Illinois from Colorado with our price prediction graph.
DEN-STL
DEN-RFD
DEN-ORD
DEN-MLI
DEN-MDW
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 Colorado to Illinois
USCO-USIL
DEN-STL
DEN-RFD
DEN-ORD
DEN-MLI
What is the cheapest month to book a flight from Colorado to Illinois?
Currently, January is the cheapest month in which you can book a flight from Colorado to Illinois (average of $248). Flying from Colorado to Illinois in July is currently the most expensive (average of $356). 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 CO to IL?
Find hourly flight availability from Colorado 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 September 14, 2026.
A simple way to save on the total cost of your ticket is to fly from Colorado to Illinois in the evening. If you’re flexible enough to do this you can expect to save up to 32% on your trip compared to booking a flight at noon.
Weekly flight availability from Colorado to Illinois
Explore weekly flight availability from Colorado 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 September 14, 2026.
The most flights from USCO to USIL are scheduled on a Friday (75 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (51 on average).
How much does it cost to fly round-trip from Colorado to Illinois?
Airfare is below average for this route at the moment.
Colorado to Illinois flights typically cost between $210 and $354 in November.The cheapest round-trip price found within the last 5 days was $121 on Frontier (Nov 13-Nov 16).
How far ahead should I book a flight from Colorado to Illinois?
To ensure you get the cheapest price possible for a flight from Colorado 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 Colorado to Illinois?
Use this chart to determine the cheapest time to fly round-trip from Colorado to Illinois. Price data was last updated on September 12, 2026.
Travelers seeking maximum savings on their Colorado to Illinois flight should consider departing on Friday at noon when fares are most often at their lowest. Tuesday at noon 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 September 14, 2026.
Read reviews from past customers who have flown Southwest,United Airlines, andAllegiant Air from Colorado to Illinois. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Boarding
8.1
Food
7.0
Comfort
8.0
Crew
8.6
Entertainment
7.5
Overall
8.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Boarding
8.1
Food
7.0
Comfort
8.0
Crew
8.6
Entertainment
7.5
Overall
8.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Boarding
8.1
Food
7.0
Comfort
8.0
Crew
8.6
Entertainment
7.5
Overall
8.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Boarding
8.1
Food
7.0
Comfort
8.0
Crew
8.6
Entertainment
7.5
Overall
8.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Boarding
8.1
Food
7.0
Comfort
8.0
Crew
8.6
Entertainment
7.5
Overall
8.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Boarding
8.1
Food
7.0
Comfort
8.0
Crew
8.6
Entertainment
7.5
Overall
8.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Related info for your journey
Find useful and relevant information for your journey from Colorado 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 Colorado 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 Colorado to Illinois by cabin class
Find flights from Colorado to Illinois, based on your preferred cabin class, be it economy, premium economy, business, or first class.
Colorado and Illinois flights
Browse other Colorado and Illinois flight options. Last updated on September 14, 2026.
Popular flight searches
Check out other popular destinations found by fellow travelers in 2026
Find a return flight route from Illinois
Find the right flight back to Colorado after your stay in Illinois
Colorado to Illinois flights
Consider these flights traveling from Colorado to Illinois.
Top 6 airlines flying from Colorado to Illinois
Discover the top 6 airlines that operate flights from Colorado to Illinois. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 7,457,451 searches. Data last updated September 14, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$82 | Average$200 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$91 | Average$218 | FlexibilityNo cancel fee | On-time88% | |
| Cheapest$138 | Average$281 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$170 | Average$348 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$172 | Average$448 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$185 | Average$438 | FlexibilityNo cancel fee | On-time69% |