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$63+ 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 9/12. Fares are subject to change and may not be available on all flights or dates of travel.
ORD — DEN
Jul 1 — Jul 81
Tue 7/1
Tue 7/8
1 adult, Economy
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Cheap flight deals from Illinois to Denver

Keep the following information in mind while searching for Illinois to Denver flight deals. Data was last updated June 26, 2025.

Round-trip from

$123
(Kiwi.com)

One-way from

$63
(Kiwi.com)

Popular in

December

Cheapest in

September

Average price

$218

Good round-trip deal

$186 or less

Good one-way deal

$111 or less
From Illinois to Denver Intl
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One-way flight from Illinois to Denver Intl
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High demand for flights, 0% potential price rise
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Cheapest flight prices on average. 2% potential price decrease ($4 potential savings vs. average RT price).
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Average for round-trip flights in June 2025
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Price to beat on a round-trip flight from Illinois to Denver Intl.
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Price to beat on a one-way flight from Illinois to Denver Intl.
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Find flight deals from Illinois to Denver

Cheapest flights from Illinois to Denver
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 June 26, 2025.

This Kiwi.com deal was found by Cheapflights users on 6/24. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/113:03 pmPIA - DEN
Nonstop2h 20mAllegiant Air
Mon 8/186:31 pmDEN - PIA
Nonstop2h 00mAllegiant Air
Deal found 6/24$123
This CheapOair deal was found by Cheapflights users on 6/24. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/17:00 amORD - DEN
Nonstop2h 49mFrontier
Tue 7/88:31 pmDEN - ORD
Nonstop2h 39mFrontier
Deal found 6/24$139
This Frontier deal was found by Cheapflights users on 6/23. Clicking the “Pick Dates” 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 8/92:44 pmMDW - DEN
Nonstop2h 49mFrontier
Sat 8/165:26 pmDEN - MDW
Nonstop2h 28mFrontier
Deal found 6/23$139
This Frontier deal was found by Cheapflights users on 6/24. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/167:29 pmSTL - DEN
Nonstop2h 29mFrontier
Mon 7/216:00 amDEN - STL
Nonstop2h 11mFrontier
Deal found 6/24$144
This American Airlines deal was found by Cheapflights users on 6/25. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/43:34 pmPIA - DEN
1 stop7h 28mAmerican Airlines
Mon 9/85:37 pmDEN - PIA
1 stop4h 42mAmerican Airlines
Deal found 6/25$149
This Southwest deal was found by Cheapflights users on 6/24. Clicking the “Pick Dates” 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 9/98:50 pmMDW - DEN
Nonstop2h 35mSouthwest
Wed 9/174:50 pmDEN - MDW
Nonstop2h 20mSouthwest
Deal found 6/24$157
This Southwest deal was found by Cheapflights users on 6/25. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/268:10 amSTL - DEN
Nonstop2h 15mSouthwest
Wed 8/277:00 amDEN - STL
Nonstop2h 00mSouthwest
Deal found 6/25$157
This American Airlines deal was found by Cheapflights users on 6/24. Clicking the “Pick Dates” 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 9/114:22 pmMLI - DEN
1 stop7h 46mAmerican Airlines
Tue 9/163:08 pmDEN - MLI
1 stop6h 17mAmerican Airlines
Deal found 6/24$159
This Southwest deal was found by Cheapflights users on 6/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/131:30 pmORD - DEN
1 stop5h 25mSouthwest
Sat 8/169:35 amDEN - ORD
Nonstop2h 30mSouthwest
Deal found 6/23$175
This American Airlines deal was found by Cheapflights users on 6/23. Clicking the “Pick Dates” 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 8/296:35 pmORD - DEN
Nonstop2h 47mAmerican Airlines
Tue 9/25:32 pmDEN - ORD
Nonstop2h 46mAmerican Airlines
Deal found 6/23$181
This American Airlines deal was found by Cheapflights users on 6/24. Clicking the “Pick Dates” 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 8/3010:08 amSTL - DEN
1 stop6h 41mAmerican Airlines
Thu 9/42:47 pmDEN - STL
1 stop7h 03mAmerican Airlines
Deal found 6/24$182
This Delta deal was found by Cheapflights users on 6/25. 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.
Tue 10/216:00 amSTL - DEN
1 stop7h 37mDelta
Wed 10/226:25 pmDEN - STL
1 stop5h 12mDelta
Deal found 6/25$197

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 June 26, 2025.
Use the filters below to find and compare flights from Illinois to Denver that are best for you.

Fly from

Illinois

Fly to

Denver

Route

Depart

Return

Price

PeoriaDenver

PIA - DEN

PIADEN

Greater Peoria

Mon 8/11

3:03 pm-4:23 pm

Nonstop2h 20m

Denver Intl

Mon 8/18

6:31 pm-9:31 pm

Nonstop2h 00m

$108

ChicagoDenver

ORD - DEN

ORDDEN

Chicago O'Hare Intl

Tue 7/1

7:00 am-8:49 am

Nonstop2h 49m

Denver Intl

Tue 7/8

8:31 pm-12:10 am

Nonstop2h 39m

$139

ChicagoDenver

MDW - DEN

MDWDEN

Chicago Midway

Sat 8/9

2:44 pm-4:33 pm

Nonstop2h 49m

Denver Intl

Sat 8/16

5:26 pm-8:54 pm

Nonstop2h 28m

$139

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Wed 7/16

7:29 pm-8:58 pm

Nonstop2h 29m

Denver Intl

Mon 7/21

6:00 am-9:11 am

Nonstop2h 11m

$144

PeoriaDenver

PIA - DEN

PIADEN

Greater Peoria

Thu 9/4

3:34 pm-10:02 pm

1 stop7h 28m

Denver Intl

Mon 9/8

5:37 pm-11:19 pm

1 stop4h 42m

$149

ChicagoDenver

MDW - DEN

MDWDEN

Chicago Midway

Tue 9/9

8:50 pm-10:25 pm

Nonstop2h 35m

Denver Intl

Wed 9/17

4:50 pm-8:10 pm

Nonstop2h 20m

$157

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Tue 8/26

8:10 am-9:25 am

Nonstop2h 15m

Denver Intl

Wed 8/27

7:00 am-10:00 am

Nonstop2h 00m

$157

MolineDenver

MLI - DEN

MLIDEN

Moline Quad-City

Thu 9/11

4:22 pm-11:08 pm

1 stop7h 46m

Denver Intl

Tue 9/16

3:08 pm-10:25 pm

1 stop6h 17m

$159

ChicagoDenver

ORD - DEN

ORDDEN

Chicago O'Hare Intl

Wed 8/13

1:30 pm-5:55 pm

1 stop5h 25m

Denver Intl

Sat 8/16

9:35 am-1:05 pm

Nonstop2h 30m

$175

ChicagoDenver

ORD - DEN

ORDDEN

Chicago O'Hare Intl

Fri 8/29

6:35 pm-8:22 pm

Nonstop2h 47m

Denver Intl

Tue 9/2

5:32 pm-9:18 pm

Nonstop2h 46m

$181

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/24

Showing 1-10 of 60 results
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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.
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

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 $197). Flying from Illinois to Denver in March is currently the most expensive (average of $278). 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 June 26, 2025.

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Illinois to Denver as you normally would.

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 June 26, 2025.

The most flights from USIL to DEN are scheduled on a Thursday (59 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (35 on average).

Rainfall in Denver by month

Plan your trip to Denver by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in Denver ranges from 0.5 - 2.3 inches per month. May is typically the wettest month, when rainfall can reach 2.3 in. January is typically the driest time to visit Denver when rainfall is around 0.5 in.

Temperature in Denver by month

Plan your trip to Denver by taking into account the average temperature totals by month.

If weather is an important factor for your trip to Denver, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 73.4 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 30.2 F).

Reviews of airlines servicing Denver

Get insights into the airlines that provide service to Denver. 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 Denver. Reviews last updated June 26, 2025.
Read reviews from past customers who have flown Alaska Airlines, Southwest, and Delta from Illinois to Denver. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Crew

8.5

Overall

8.0

Entertainment

7.1

Food

7.1

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Crew

8.5

Overall

8.0

Entertainment

7.1

Food

7.1

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Southwest
8.0
Very good
4,278 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Crew

8.5

Overall

8.0

Entertainment

7.1

Food

7.1

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Delta
8.0
Very good
7,964 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Crew

8.5

Overall

8.0

Entertainment

7.1

Food

7.1

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
United Airlines
7.4
Good
8,840 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Crew

8.5

Overall

8.0

Entertainment

7.1

Food

7.1

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
American Airlines
7.2
Good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Crew

8.5

Overall

8.0

Entertainment

7.1

Food

7.1

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

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.

  • What airport do you fly into for flights to Denver from Illinois?

    For a flight from Illinois to Denver, you will be flying into Denver Intl. Denver Intl (DEN) is just 18.5 mi from the center of the city.

  • What are the cheapest airlines to fly from Illinois to Denver one-way?

    The cheapest airlines for a one-way flight from Illinois to Denver are Allegiant Air ($63), United Airlines ($79), and Southwest ($79).

  • What are the most popular routes from Illinois to Denver?

    While some choose either Chicago Midway - Denver Intl or Lambert-St Louis - Denver Intl, Chicago O'Hare Intl - Denver Intl is the most popular route from Illinois to Denver.

  • What are the most reliable airlines from Illinois to Denver?

    The top 3 most reliable airlines when flying from Illinois to Denver are Envoy Air (100%), Copa Airlines (80%) and Royal Jordanian (75%).

  • What are the cheapest flights from Illinois to Denver?

    While on average a flight from Illinois to Denver is generally $822, our data shows the cheapest flight currently is $85. When looking at the most popular route, (Chicago O'Hare Intl - Denver Intl), you can expect to pay $118 for that flight.

  • Can I find deals for flights from Illinois to Denver that include hotel bookings?

    Yes. In addition to deals on Illinois to Denver flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Illinois to Denver?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Illinois to Denver.

  • Can I find deals for business class flights from Illinois to Denver?

    Yes. Cheapflights offers flight deals from Illinois to Denver by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • 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 $197). Flying from Illinois to Denver in March is currently the most expensive (average of $278). 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.

See more FAQs

Traveling to a place near Illinois?

Book flights to Illinois if you plan to visit one of these locations
Westminster
Black Hawk
Winter Park
Lakewood
Cripple Creek
Golden
Brighton
Silverthorne
Thornton
Frisco
Broomfield
Grand Lake
Central City
Fort Morgan
Glendale
Copper Mountain
Wheat Ridge
Longmont
Idaho Springs
Greeley

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Alternative routes for Illinois to Denver

See prices for flight routes from nearby airports that may be better suited for you.
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Burbank to Denver flights

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 June 26, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$48Average$155FlexibilityNo cancel feeOn-time62%
Allegiant AirCheapest$90Average$148FlexibilityNo cancel feeOn-time88%
American AirlinesCheapest$153Average$370FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$157Average$354FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$159Average$259FlexibilityNo cancel feeOn-time63%
DeltaCheapest$228Average$248FlexibilityNo cancel feeOn-timeN/A

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