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$67+ 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 9/26. Fares are subject to change and may not be available on all flights or dates of travel.
ORD — DEN
mai 6 — mai 131
ter 5/6
ter 5/13
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 maio 1, 2025.

Most accurate provider

CheapOair
3 stars

Most trusted provider

CheapOair
3 stars

Round-trip from

$117
(Cheapflightsfares)

One-way from

$76
(United Airlines)

Popular in

December

Cheapest in

September

Average price

$173

Good round-trip deal

$184 or less

Good one-way deal

$94 or less
Provider with most accurate pricing for Chicago (CHI)-Denver Intl flight deals.
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Provider most trusted by Cheapflights users for Chicago (CHI)-Denver Intl flights.
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From Illinois to Denver Intl
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One-way flight from Illinois to Denver Intl
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Highest demand for flights based on searches. 4% potential increase in price ($7 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($5 potential savings vs. average RT price).
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Average for round-trip flights in May 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 maio 1, 2025.

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.
qua 6/118:11 pmSTL - DEN
Nonstop2h 30mFrontier
qua 6/186:00 amDEN - STL
Nonstop2h 12mFrontier
Deal found 4/30$117
This Booking.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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
seg 6/233:48 pmPIA - DEN
Nonstop2h 18mAllegiant Air
seg 6/305:56 pmDEN - PIA
Nonstop2h 04mAllegiant Air
Deal found 4/30$119
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.
sex 6/135:40 amORD - DEN
Nonstop2h 52mFrontier
sex 6/208:21 pmDEN - ORD
Nonstop2h 38mFrontier
Deal found 4/30$121
This Southwest deal was found by Cheapflights users on 5/1. 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.
ter 7/155:15 amMDW - DEN
Nonstop2h 35mSouthwest
qua 7/165:30 amDEN - MDW
Nonstop2h 25mSouthwest
Deal found 5/1$151
This American Airlines deal was found by Cheapflights users on 5/1. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
ter 6/33:24 pmORD - DEN
Nonstop2h 43mAmerican Airlines
ter 6/107:21 amDEN - ORD
Nonstop2h 40mAmerican Airlines
Deal found 5/1$151
This CheapOair deal was found by Cheapflights users on 5/1. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
qui 6/262:44 pmMDW - DEN
Nonstop2h 52mFrontier
sáb 6/285:26 pmDEN - MDW
Nonstop2h 27mFrontier
Deal found 5/1$154
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.
ter 6/39:40 pmORD - DEN
Nonstop2h 50mUnited Airlines
seg 6/95:45 pmDEN - ORD
Nonstop2h 35mUnited Airlines
Deal found 4/29$160
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.
sáb 5/245:25 pmORD - DEN
Nonstop2h 50mSouthwest
qua 5/2810:35 amDEN - ORD
2 stops9h 55mSouthwest
Deal found 4/30$166
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.
sex 7/2510:40 amORD - DEN
1 stop4h 00mMultiple Airlines
sex 7/258:21 pmDEN - ORD
Nonstop2h 39mMultiple Airlines
Deal found 4/30$192
This Southwest deal was found by Cheapflights users on 5/1. 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.
qua 6/45:55 amSTL - DEN
Nonstop2h 20mSouthwest
sáb 6/77:50 pmDEN - STL
Nonstop2h 05mSouthwest
Deal found 5/1$197
This Delta 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
sex 5/165:15 pmMLI - DEN
1 stop8h 01mDelta
ter 5/207:00 amDEN - MLI
1 stop8h 34mDelta
Deal found 4/30$209
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.
qua 7/24:45 pmSTL - DEN
Nonstop2h 24mUnited Airlines
ter 7/81:25 pmDEN - STL
Nonstop2h 04mUnited Airlines
Deal found 4/30$210

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 maio 1, 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

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

qua 6/11

8:11 pm-9:41 pm

Nonstop2h 30m

Denver Intl

qua 6/18

6:00 am-9:12 am

Nonstop2h 12m

$117

PeoriaDenver

PIA - DEN

PIADEN

Greater Peoria

seg 6/23

3:48 pm-5:06 pm

Nonstop2h 18m

Denver Intl

seg 6/30

5:56 pm-9:00 pm

Nonstop2h 04m

$119

ChicagoDenver

ORD - DEN

ORDDEN

Chicago O'Hare Intl

sex 6/13

5:40 am-7:32 am

Nonstop2h 52m

Denver Intl

sex 6/20

8:21 pm-11:59 pm

Nonstop2h 38m

$121

ChicagoDenver

ORD - DEN

ORDDEN

Chicago O'Hare Intl

ter 6/3

3:24 pm-5:07 pm

Nonstop2h 43m

Denver Intl

ter 6/10

7:21 am-11:01 am

Nonstop2h 40m

$151

ChicagoDenver

MDW - DEN

MDWDEN

Chicago Midway

ter 7/15

5:15 am-6:50 am

Nonstop2h 35m

Denver Intl

qua 7/16

5:30 am-8:55 am

Nonstop2h 25m

$151

ChicagoDenver

MDW - DEN

MDWDEN

Chicago Midway

qui 6/26

2:44 pm-4:36 pm

Nonstop2h 52m

Denver Intl

sáb 6/28

5:26 pm-8:53 pm

Nonstop2h 27m

$154

ChicagoDenver

ORD - DEN

ORDDEN

Chicago O'Hare Intl

ter 6/3

9:40 pm-11:30 pm

Nonstop2h 50m

Denver Intl

seg 6/9

5:45 pm-9:20 pm

Nonstop2h 35m

$160

ChicagoDenver

ORD - DEN

ORDDEN

Chicago O'Hare Intl

sáb 5/24

5:25 pm-7:15 pm

Nonstop2h 50m

Denver Intl

qua 5/28

10:35 am-9:30 pm

2 stops9h 55m

$166

ChicagoDenver

ORD - DEN

ORDDEN

Chicago O'Hare Intl

sex 7/25

10:40 am-1:40 pm

1 stop4h 00m

Denver Intl

sex 7/25

8:21 pm-12:00 am

Nonstop2h 39m

$192

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

qua 6/4

5:55 am-7:15 am

Nonstop2h 20m

Denver Intl

sáb 6/7

7:50 pm-10:55 pm

Nonstop2h 05m

$197

Flights are sorted by cheapest round-trip flights first.

Deals found on 5/1

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 maio 1, 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 maio 1, 2025.

The most flights from USIL to DEN are scheduled on a Thursday (54 on average). You will have fewer flight options on Monday, which is when the least amount of flights are scheduled (27 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 maio 1, 2025.
Get a feel of what it's like to fly with Alaska Airlines, Southwest and Delta from Illinois to Denver by reading reviews from past customers. In addition to providing an overall rating, users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
9,972 reviews

Food

7.1

Entertainment

7.1

Boarding

8.1

Crew

8.5

Overall

8.0

Comfort

7.9

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
9,972 reviews
Alaska Airlines
8.0
Very good
9,972 reviews

Food

7.1

Entertainment

7.1

Boarding

8.1

Crew

8.5

Overall

8.0

Comfort

7.9

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
4,293 reviews
Alaska Airlines
8.0
Very good
9,972 reviews

Food

7.1

Entertainment

7.1

Boarding

8.1

Crew

8.5

Overall

8.0

Comfort

7.9

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
7,934 reviews
Alaska Airlines
8.0
Very good
9,972 reviews

Food

7.1

Entertainment

7.1

Boarding

8.1

Crew

8.5

Overall

8.0

Comfort

7.9

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
8,696 reviews
Alaska Airlines
8.0
Very good
9,972 reviews

Food

7.1

Entertainment

7.1

Boarding

8.1

Crew

8.5

Overall

8.0

Comfort

7.9

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Allegiant Air
7.3
Good
734 reviews
Alaska Airlines
8.0
Very good
9,972 reviews

Food

7.1

Entertainment

7.1

Boarding

8.1

Crew

8.5

Overall

8.0

Comfort

7.9

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 United Airlines ($76), Southwest ($76), and Frontier ($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 Frontier (94%), Copa Airlines (93%) and Austrian Airlines (90%).

  • What are the cheapest flights from Illinois to Denver?

    While on average a flight from Illinois to Denver is generally $536, our data shows the cheapest flight currently is $79. When looking at the most popular route, (Chicago O'Hare Intl - Denver Intl), you can expect to pay $106 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
Silverthorne
Brighton
Golden
Thornton
Greeley
Frisco
Grand Lake
Broomfield
Central City
Glendale
Copper Mountain
Wheat Ridge
Longmont
Idaho Springs
Limon

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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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Sacramento to Denver flights

Top 5 airlines flying from Illinois to Denver

Discover the top 5 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 maio 1, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$47Average$152FlexibilityNo cancel feeOn-time62%
Allegiant AirCheapest$92Average$154FlexibilityNo cancel feeOn-time88%
American AirlinesCheapest$147Average$376FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$154Average$337FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$159Average$265FlexibilityNo cancel feeOn-time63%

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