$69+ 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 9/15. Fares are subject to change and may not be available on all flights or dates of travel.
DEN — ORD
Jul 8 — Jul 151
1 adult, Economy
We work with more than 300 partners to bring you better travel deals
Find cheap flights from Denver 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
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 Denver to Illinois
Keep the following information in mind while searching for Denver to Illinois flight deals. Data was last updated July 3, 2025.
Round-trip from | $136 (Frontier) |
|---|---|
One-way from | $69 (Booking.com) |
Popular in | May |
Cheapest in | September |
Average price | $205 |
Good round-trip deal | $186 or less |
Good one-way deal | $79 or less |
Find flight deals from Denver to Illinois
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 July 3, 2025.
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 July 3, 2025.
This Booking.com deal was found by Cheapflights users on 7/2. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/36:41 pmDEN - PIA
Nonstop1h 51mAllegiant Air
Mon 10/611:59 amPIA - DEN
Nonstop2h 16mAllegiant Air
Deal found 7/2![Allegiant Air logo]()
$72
This Kiwi.com deal was found by Cheapflights users on 7/3. 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 10/88:44 pmDEN - STL
1 stop11h 08mFrontier
Sat 10/117:52 pmSTL - DEN
Nonstop2h 28mFrontier
Deal found 7/3![Frontier logo]()
$135
This Priceline deal was found by Cheapflights users on 7/3. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 7/208:31 pmDEN - ORD
Nonstop2h 39mFrontier
Thu 8/75:40 amORD - DEN
Nonstop2h 50mFrontier
Deal found 7/3![Frontier logo]()
$149
This Priceline deal was found by Cheapflights users on 7/2. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/2312:54 amDEN - MDW
1 stop8h 14mFrontier
Sat 8/306:10 amMDW - DEN
1 stop9h 08mFrontier
Deal found 7/2![Frontier logo]()
$153
This American Airlines deal was found by Cheapflights users on 7/3. 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 12/107:20 amDEN - ORD
Nonstop2h 45mAmerican Airlines
Mon 12/1511:45 amORD - DEN
Nonstop2h 43mAmerican Airlines
Deal found 7/3![American Airlines logo]()
$157
This Southwest deal was found by Cheapflights users on 7/2. 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 8/288:45 pmDEN - MDW
Nonstop2h 20mSouthwest
Sat 8/307:25 pmMDW - DEN
Nonstop2h 40mSouthwest
Deal found 7/2![Southwest logo]()
$157
This Southwest deal was found by Cheapflights users on 7/3. 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.
Tue 8/57:10 amDEN - STL
Nonstop2h 00mSouthwest
Mon 8/114:25 pmSTL - DEN
1 stop4h 50mSouthwest
Deal found 7/3![Southwest logo]()
$167
This Southwest deal was found by Cheapflights users on 7/1. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/1610:25 amDEN - ORD
2 stops10h 05mSouthwest
Sat 9/207:00 amORD - DEN
Nonstop2h 40mSouthwest
Deal found 7/1![Southwest logo]()
$172
This American Airlines deal was found by Cheapflights users on 6/30. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/292:47 pmDEN - PIA
1 stop7h 02mAmerican Airlines
Tue 9/306:15 pmPIA - DEN
1 stop5h 01mAmerican Airlines
Deal found 6/30![American Airlines logo]()
$203
This United Airlines deal was found by Cheapflights users on 7/3. 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.
Fri 8/225:59 pmDEN - PIA
Nonstop2h 13mUnited Airlines
Wed 8/278:45 amPIA - DEN
Nonstop2h 41mUnited Airlines
Deal found 7/3![United Airlines logo]()
$209
This United Airlines deal was found by Cheapflights users on 7/1. 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 9/105:39 pmDEN - MLI
Nonstop2h 14mUnited Airlines
Tue 9/169:00 amMLI - DEN
Nonstop2h 29mUnited Airlines
Deal found 7/1![United Airlines logo]()
$209
This American Airlines deal was found by Cheapflights users on 7/2. 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 8/87:02 amDEN - MLI
1 stop7h 48mAmerican Airlines
Mon 8/115:50 pmMLI - DEN
1 stop5h 25mAmerican Airlines
Deal found 7/2![American Airlines logo]()
$229
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 July 3, 2025.
Use the filters below to find and compare flights from Denver to Illinois that are best for you.
Fly from
Denver
Fly to
Illinois
Route
Depart
Return
Price
DenverPeoria
DEN - PIA
DENPIA
Denver Intl
Fri 10/3
6:41 pm-9:32 pm
Nonstop1h 51m
Greater Peoria
Mon 10/6
11:59 am-1:15 pm
Nonstop2h 16m
$72
DenverSt. Louis
DEN - STL
DENSTL
Denver Intl
Wed 8/6
6:00 am-9:11 am
Nonstop2h 11m
Lambert-St Louis
Wed 8/13
7:29 pm-8:58 pm
Nonstop2h 29m
$135
DenverChicago
DEN - ORD
DENORD
Denver Intl
Sun 7/20
8:31 pm-12:10 am
Nonstop2h 39m
Chicago O'Hare Intl
Thu 8/7
5:40 am-7:30 am
Nonstop2h 50m
$149
DenverChicago
DEN - MDW
DENMDW
Denver Intl
Sat 8/23
12:54 am-10:08 am
1 stop8h 14m
Chicago Midway
Sat 8/30
6:10 am-2:18 pm
1 stop9h 08m
$153
DenverChicago
DEN - ORD
DENORD
Denver Intl
Thu 8/7
7:22 am-10:53 am
Nonstop2h 31m
Chicago O'Hare Intl
Mon 8/11
7:10 am-8:51 am
Nonstop2h 41m
$157
DenverChicago
DEN - MDW
DENMDW
Denver Intl
Thu 8/28
8:45 pm-12:05 am
Nonstop2h 20m
Chicago Midway
Tue 9/2
8:50 pm-10:25 pm
Nonstop2h 35m
$157
DenverSt. Louis
DEN - STL
DENSTL
Denver Intl
Thu 8/7
5:30 am-8:30 am
Nonstop2h 00m
Lambert-St Louis
Tue 8/12
10:45 am-4:05 pm
2 stops6h 20m
$168
DenverChicago
DEN - ORD
DENORD
Denver Intl
Tue 9/16
10:25 am-9:30 pm
2 stops10h 05m
Chicago O'Hare Intl
Sat 9/20
7:00 am-8:40 am
Nonstop2h 40m
$172
DenverPeoria
DEN - PIA
DENPIA
Denver Intl
Fri 8/29
2:47 pm-10:49 pm
1 stop7h 02m
Greater Peoria
Tue 9/30
6:15 pm-10:16 pm
1 stop5h 01m
$203
DenverPeoria
DEN - PIA
DENPIA
Denver Intl
Fri 8/22
5:59 pm-9:12 pm
Nonstop2h 13m
Greater Peoria
Wed 8/27
8:45 am-10:26 am
Nonstop2h 41m
$209
Showing 1-10 of 51 results
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.
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
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 $245). Flying from Denver to Illinois in March is currently the most expensive (average of $321). 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 July 3, 2025.
Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Denver to Illinois as you normally would.
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 July 3, 2025.
The most flights from DEN to USIL are scheduled on a Thursday (66 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (22 on average).
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 July 3, 2025.
Read through reviews of airlines operating flights from Denver to Illinois, such as Southwest, Delta, and United Airlines. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Overall
8.0
Crew
8.6
Entertainment
7.6
Boarding
8.2
Food
7.0
Comfort
8.0
Reviews
1 / 20
8.0
ExcellentJohn,May 2025
PVD - BNA
Overall
8.0
Crew
8.6
Entertainment
7.6
Boarding
8.2
Food
7.0
Comfort
8.0
Reviews
1 / 20
8.0
ExcellentJohn,May 2025
PVD - BNA
Overall
8.0
Crew
8.6
Entertainment
7.6
Boarding
8.2
Food
7.0
Comfort
8.0
Reviews
1 / 20
8.0
ExcellentJohn,May 2025
PVD - BNA
Overall
8.0
Crew
8.6
Entertainment
7.6
Boarding
8.2
Food
7.0
Comfort
8.0
Reviews
1 / 20
8.0
ExcellentJohn,May 2025
PVD - BNA
Overall
8.0
Crew
8.6
Entertainment
7.6
Boarding
8.2
Food
7.0
Comfort
8.0
Reviews
1 / 20
8.0
ExcellentJohn,May 2025
PVD - BNA
Overall
8.0
Crew
8.6
Entertainment
7.6
Boarding
8.2
Food
7.0
Comfort
8.0
Reviews
1 / 20
8.0
ExcellentJohn,May 2025
PVD - BNA
Related info for your journey
Find useful and relevant information for your journey from Denver to Illinois. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
Browse thousands of different options on Cheapflights for your next trip
Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.
Alternative routes for Denver to Illinois
See prices for flight routes from nearby airports that may be better suited for you.
Top 5 airlines flying from Denver to Illinois
Discover the top 5 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 July 3, 2025.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$54 | Average$169 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$84 | Average$166 | FlexibilityNo cancel fee | On-time88% | |
| Cheapest$151 | Average$402 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$155 | Average$249 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$159 | Average$364 | FlexibilityNo cancel fee | On-time69% |