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$43+ 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 12/20. Fares are subject to change and may not be available on all flights or dates of travel.
ORD — DEN
Nov 25 — Dec 21
Mon 11/25
Mon 12/2
1 adult, Economy
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Cheap flight deals from Illinois to Denver

Discover tips and strategies to find the most affordable flight options for your journey from Illinois (USIL) to Denver (DEN). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated November 20, 2024.

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 November 20, 2024.

This Cheapflightsfares deal was found by Cheapflights users on 11/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/116:46 pmSTL - DEN
Nonstop2h 36mFrontier
Mon 12/165:05 amDEN - STL
Nonstop2h 08mFrontier
Deal found 11/19$67
This Cheapflightsfares deal was found by Cheapflights users on 11/19. 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.
Mon 12/97:25 amORD - DEN
Nonstop3h 01mFrontier
Thu 12/1210:26 amDEN - ORD
Nonstop2h 34mFrontier
Deal found 11/19$77
This Cheapflightsfares deal was found by Cheapflights users on 11/19. 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 12/127:15 amMDW - DEN
Nonstop2h 50mFrontier
Sun 12/158:55 pmDEN - MDW
Nonstop2h 18mFrontier
Deal found 11/19$77
This Mytrip deal was found by Cheapflights users on 11/20. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/219:08 amPIA - DEN
Nonstop2h 25mAllegiant Air
Fri 12/276:39 pmDEN - PIA
Nonstop1h 59mAllegiant Air
Deal found 11/20$100
This Booking.com deal was found by Cheapflights users on 11/19. 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.
Thu 12/127:25 amORD - DEN
Nonstop3h 01mMultiple Airlines
Mon 12/165:40 pmDEN - ORD
1 stop15h 51mMultiple Airlines
Deal found 11/19$153
This American Airlines deal was found by Cheapflights users on 11/20. 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 12/118:50 pmORD - DEN
Nonstop2h 46mAmerican Airlines
Tue 12/177:00 amDEN - ORD
Nonstop2h 45mAmerican Airlines
Deal found 11/20$169
This Southwest deal was found by Cheapflights users on 11/19. 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 12/248:35 pmMDW - DEN
Nonstop2h 45mSouthwest
Mon 12/308:55 pmDEN - MDW
Nonstop2h 20mSouthwest
Deal found 11/19$170
This Southwest deal was found by Cheapflights users on 11/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/146:30 amORD - DEN
Nonstop2h 40mSouthwest
Sun 12/157:05 amDEN - ORD
Nonstop2h 40mSouthwest
Deal found 11/19$184
This United Airlines deal was found by Cheapflights users on 11/20. 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 12/137:46 pmORD - DEN
Nonstop2h 49mUnited Airlines
Sun 12/227:40 pmDEN - ORD
Nonstop2h 30mUnited Airlines
Deal found 11/20$187
This United Airlines deal was found by Cheapflights users on 11/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/174:31 pmSTL - DEN
Nonstop2h 31mUnited Airlines
Tue 12/241:25 pmDEN - STL
Nonstop2h 06mUnited Airlines
Deal found 11/18$197
This United Airlines deal was found by Cheapflights users on 11/19. 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 12/138:57 amMLI - DEN
Nonstop2h 38mUnited Airlines
Mon 12/165:48 pmDEN - MLI
Nonstop2h 12mUnited Airlines
Deal found 11/19$209
This Delta deal was found by Cheapflights users on 11/20. 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 12/1112:25 pmORD - DEN
1 stop4h 47mDelta
Wed 12/182:23 pmDEN - ORD
1 stop4h 22mDelta
Deal found 11/20$216

Find flights from Illinois to Denver within your budget

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 2,629,791 searches. Data last updated November 20, 2024.

Fly from

Any airport

Fly to

Any airport

Route

Depart

Return

Price

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Wed 12/11

6:46 pm-8:22 pm

Nonstop2h 36m

Denver Intl

Mon 12/16

5:05 am-8:13 am

Nonstop2h 08m

$67

ChicagoDenver

ORD - DEN

ORDDEN

Chicago O'Hare Intl

Sun 2/9

7:25 am-9:15 am

Nonstop2h 50m

Denver Intl

Sat 2/15

1:52 pm-5:25 pm

Nonstop2h 33m

$76

ChicagoDenver

MDW - DEN

MDWDEN

Chicago Midway

Thu 1/23

7:15 am-9:09 am

Nonstop2h 54m

Denver Intl

Sun 1/26

8:55 pm-12:17 am

Nonstop2h 22m

$76

PeoriaDenver

PIA - DEN

PIADEN

Greater Peoria

Mon 2/3

11:15 am-12:43 pm

Nonstop2h 28m

Denver Intl

Fri 2/7

1:33 pm-4:38 pm

Nonstop2h 05m

$84

ChicagoDenver

ORD - DEN

ORDDEN

Chicago O'Hare Intl

Thu 12/12

7:25 am-9:26 am

Nonstop3h 01m

Denver Intl

Mon 12/16

5:40 pm-10:31 am

1 stop15h 51m

$153

ChicagoDenver

ORD - DEN

ORDDEN

Chicago O'Hare Intl

Fri 1/3

9:19 pm-11:07 pm

Nonstop2h 48m

Denver Intl

Wed 1/15

8:07 am-11:45 am

Nonstop2h 38m

$163

ChicagoDenver

MDW - DEN

MDWDEN

Chicago Midway

Tue 12/24

8:35 pm-10:20 pm

Nonstop2h 45m

Denver Intl

Mon 12/30

8:55 pm-12:15 am

Nonstop2h 20m

$170

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Sun 2/9

4:36 pm-6:13 pm

Nonstop2h 37m

Denver Intl

Tue 2/11

9:40 am-12:48 pm

Nonstop2h 08m

$177

ChicagoDenver

ORD - DEN

ORDDEN

Chicago O'Hare Intl

Tue 12/17

12:45 pm-2:34 pm

Nonstop2h 49m

Denver Intl

Tue 12/24

6:00 pm-9:30 pm

Nonstop2h 30m

$183

ChicagoDenver

ORD - DEN

ORDDEN

Chicago O'Hare Intl

Wed 12/4

7:00 am-8:45 am

Nonstop2h 45m

Denver Intl

Wed 12/11

7:05 pm-10:35 pm

Nonstop2h 30m

$200

Flights are sorted by cheapest round-trip flights first.

Deals found on 11/19

Showing 1-10 of 58 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.

Travel insights for flights from Illinois to Denver

Get recent, data-driven insights about flights from Illinois to Denver including ideal travel times, pricing trends, and more.

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 $270). 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 November 20, 2024.

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 November 20, 2024.

The most flights from USIL to DEN are scheduled on a Wednesday (53 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (22 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 November 20, 2024.
Get a feel of what it's like to fly with Frontier, United Airlines and American Airlines 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.
Southwest
8.1
Very good
5,014 reviews

Boarding

8.2

Overall

8.1

Crew

8.7

Entertainment

7.7

Comfort

8.1

Food

7.2

Reviews

1 / 10

My first time, surprisingly good! It was a good ride overall. Coming from Singapore, this budget flight is better than the budget airline for our national carrier Singapore Airlines.

Southwest
8.1
Very good
5,014 reviews
Southwest
8.1
Very good
5,014 reviews

Boarding

8.2

Overall

8.1

Crew

8.7

Entertainment

7.7

Comfort

8.1

Food

7.2

Reviews

1 / 10

My first time, surprisingly good! It was a good ride overall. Coming from Singapore, this budget flight is better than the budget airline for our national carrier Singapore Airlines.

Alaska Airlines
8.0
Very good
9,461 reviews
Southwest
8.1
Very good
5,014 reviews

Boarding

8.2

Overall

8.1

Crew

8.7

Entertainment

7.7

Comfort

8.1

Food

7.2

Reviews

1 / 10

My first time, surprisingly good! It was a good ride overall. Coming from Singapore, this budget flight is better than the budget airline for our national carrier Singapore Airlines.

Delta
8.0
Very good
8,756 reviews
Southwest
8.1
Very good
5,014 reviews

Boarding

8.2

Overall

8.1

Crew

8.7

Entertainment

7.7

Comfort

8.1

Food

7.2

Reviews

1 / 10

My first time, surprisingly good! It was a good ride overall. Coming from Singapore, this budget flight is better than the budget airline for our national carrier Singapore Airlines.

United Airlines
7.4
Good
9,171 reviews
Southwest
8.1
Very good
5,014 reviews

Boarding

8.2

Overall

8.1

Crew

8.7

Entertainment

7.7

Comfort

8.1

Food

7.2

Reviews

1 / 10

My first time, surprisingly good! It was a good ride overall. Coming from Singapore, this budget flight is better than the budget airline for our national carrier Singapore Airlines.

Allegiant Air
7.4
Good
850 reviews
Southwest
8.1
Very good
5,014 reviews

Boarding

8.2

Overall

8.1

Crew

8.7

Entertainment

7.7

Comfort

8.1

Food

7.2

Reviews

1 / 10

My first time, surprisingly good! It was a good ride overall. Coming from Singapore, this budget flight is better than the budget airline for our national carrier Singapore Airlines.

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 Frontier ($43), Allegiant Air ($63), and United Airlines ($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 Air Canada (90%), Southwest (89%) and Japan Airlines (88%).

  • What are the cheapest flights from Illinois to Denver?

    While on average a flight from Illinois to Denver is generally $749, our data shows the cheapest flight currently is $50. When looking at the most popular route, (Chicago O'Hare Intl - Denver Intl), you can expect to pay $91 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 $270). 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

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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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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 2,629,791 searches. Data last updated November 20, 2024.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$39Average$149FlexibilityNo cancel feeOn-time62%
Allegiant AirCheapest$93Average$177FlexibilityNo cancel feeOn-time88%
American AirlinesCheapest$139Average$378FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$153Average$358FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$156Average$253FlexibilityNo cancel feeOn-time63%
DeltaCheapest$185Average$459FlexibilityNo cancel feeOn-timeN/A
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