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$30+ 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 4/5. Fares are subject to change and may not be available on all flights or dates of travel.
DEN — ORD
févr. 25 — mars 41
mar. 2/25
mar. 3/4
1 adult, Economy
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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 février 20, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$63
(Frontier)

One-way from

$31
(Trip.com)

Popular in

December

Cheapest in

April

Average price

$174

Good round-trip deal

$99 or less

Good one-way deal

$72 or less
Provider with most accurate pricing for Denver Intl-Chicago (CHI) flight deals.
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Provider most trusted by Cheapflights users for Denver Intl-Chicago (CHI) flights.
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From Denver Intl to Illinois
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One-way flight from Denver Intl to Illinois
Search Deals
Highest demand for flights based on searches. 13% potential increase in price ($25 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($4 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in February 2025
Search Deals
Price to beat on a round-trip flight from Denver Intl to Illinois.
Search Deals
Price to beat on a one-way flight from Denver Intl to Illinois.
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Find flight deals from Denver to Illinois

Cheapest flights from Denver to Illinois
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 février 20, 2025.

This Frontier deal was found by Cheapflights users on 2/19. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jeu. 5/112:00 pmDEN - STL
Nonstop2h 07mFrontier
sam. 5/36:53 pmSTL - DEN
Nonstop2h 29mFrontier
Deal found 2/19$63
This Frontier deal was found by Cheapflights users on 2/19. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
lun. 3/249:08 pmDEN - ORD
Nonstop2h 36mFrontier
dim. 3/306:50 amORD - DEN
Nonstop3h 03mFrontier
Deal found 2/19$77
This Frontier deal was found by Cheapflights users on 2/19. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
lun. 3/248:55 pmDEN - MDW
Nonstop2h 22mFrontier
dim. 3/306:40 amMDW - DEN
Nonstop2h 52mFrontier
Deal found 2/19$77
This Mytrip deal was found by Cheapflights users on 2/20. 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.
ven. 4/115:17 pmDEN - PIA
Nonstop2h 00mAllegiant Air
lun. 4/143:08 pmPIA - DEN
Nonstop2h 19mAllegiant Air
Deal found 2/20$86
This American Airlines deal was found by Cheapflights users on 2/20. 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.
mer. 5/77:00 amDEN - ORD
Nonstop2h 32mAmerican Airlines
sam. 5/103:24 pmORD - DEN
Nonstop2h 43mAmerican Airlines
Deal found 2/20$159
This Southwest deal was found by Cheapflights users on 2/20. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mer. 5/77:25 pmDEN - MDW
Nonstop2h 25mSouthwest
sam. 5/108:35 pmMDW - DEN
Nonstop2h 45mSouthwest
Deal found 2/20$159
This Southwest deal was found by Cheapflights users on 2/20. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jeu. 4/247:30 pmDEN - ORD
Nonstop2h 35mSouthwest
sam. 4/267:00 amORD - DEN
Nonstop2h 40mSouthwest
Deal found 2/20$164
This Booking.com deal was found by Cheapflights users on 2/19. 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.
jeu. 6/1912:16 pmDEN - ORD
1 stop5h 55mMultiple Airlines
lun. 6/235:35 amORD - DEN
Nonstop2h 52mMultiple Airlines
Deal found 2/19$192
This United Airlines deal was found by Cheapflights users on 2/19. 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.
ven. 10/313:20 pmDEN - ORD
Nonstop2h 26mUnited Airlines
dim. 11/27:15 amORD - DEN
Nonstop2h 40mUnited Airlines
Deal found 2/19$205
This United Airlines deal was found by Cheapflights users on 2/20. 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.
ven. 4/115:50 pmDEN - MLI
Nonstop2h 13mUnited Airlines
dim. 4/138:55 amMLI - DEN
Nonstop2h 35mUnited Airlines
Deal found 2/20$210
This Delta deal was found by Cheapflights users on 2/20. 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.
jeu. 4/36:23 amDEN - ORD
1 stop5h 18mDelta
lun. 4/75:00 pmORD - DEN
1 stop5h 38mDelta
Deal found 2/20$216
This Delta deal was found by Cheapflights users on 2/20. 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.
mar. 4/812:55 amDEN - MDW
1 stop7h 12mDelta
sam. 4/129:23 amMDW - DEN
1 stop5h 30mDelta
Deal found 2/20$217

Find flights from Denver to Illinois within your budget

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 février 20, 2025.

Fly from

Denver

Fly to

Illinois

Route

Depart

Return

Price

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

jeu. 5/1

12:00 pm-3:07 pm

Nonstop2h 07m

Lambert-St Louis

sam. 5/3

6:53 pm-8:22 pm

Nonstop2h 29m

$63

DenverChicago

DEN - ORD

DENORD

Denver Intl

lun. 3/24

9:08 pm-12:44 am

Nonstop2h 36m

Chicago O'Hare Intl

dim. 3/30

6:50 am-8:53 am

Nonstop3h 03m

$77

DenverChicago

DEN - MDW

DENMDW

Denver Intl

lun. 3/24

8:55 pm-12:17 am

Nonstop2h 22m

Chicago Midway

dim. 3/30

6:40 am-8:32 am

Nonstop2h 52m

$77

DenverPeoria

DEN - PIA

DENPIA

Denver Intl

ven. 4/11

5:17 pm-8:17 pm

Nonstop2h 00m

Greater Peoria

lun. 4/14

3:08 pm-4:27 pm

Nonstop2h 19m

$86

DenverChicago

DEN - ORD

DENORD

Denver Intl

mer. 5/7

1:45 pm-5:31 pm

Nonstop2h 46m

Chicago O'Hare Intl

sam. 5/10

9:20 pm-11:08 pm

Nonstop2h 48m

$159

DenverChicago

DEN - MDW

DENMDW

Denver Intl

mer. 5/7

7:25 pm-10:50 pm

Nonstop2h 25m

Chicago Midway

sam. 5/10

8:35 pm-10:20 pm

Nonstop2h 45m

$159

DenverChicago

DEN - ORD

DENORD

Denver Intl

jeu. 4/24

7:30 pm-11:05 pm

Nonstop2h 35m

Chicago O'Hare Intl

sam. 4/26

7:00 am-8:40 am

Nonstop2h 40m

$164

DenverChicago

DEN - ORD

DENORD

Denver Intl

ven. 2/28

6:08 pm-8:56 pm

1 stop25h 48m

Chicago O'Hare Intl

ven. 3/7

6:30 am-8:33 am

Nonstop3h 03m

$203

DenverMoline

DEN - MLI

DENMLI

Denver Intl

ven. 4/11

5:50 pm-9:03 pm

Nonstop2h 13m

Moline Quad-City

dim. 4/13

8:55 am-10:30 am

Nonstop2h 35m

$210

DenverChicago

DEN - ORD

DENORD

Denver Intl

jeu. 4/3

6:23 am-12:41 pm

1 stop5h 18m

Chicago O'Hare Intl

lun. 4/7

5:00 pm-9:38 pm

1 stop5h 38m

$216

Flights are sorted by cheapest round-trip flights first.

Deals found on 2/20

Showing 1-10 of 59 results
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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.

Travel insights for flights from Denver to Illinois

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

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 février 20, 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 février 20, 2025.

The most flights from DEN to USIL are scheduled on a Thursday (48 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (15 on average).

Rainfall in Illinois by month

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

In terms of precipitation, rainfall in Illinois ranges from 1.7 - 4.9 inches per month. August is typically the wettest month, when rainfall can reach 4.9 in. January is typically the driest time to visit Illinois when rainfall is around 1.7 in.

Temperature in Illinois by month

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

If weather is an important factor for your trip to Illinois, 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 23.0 F).

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 février 20, 2025.
Get a feel of what it's like to fly with Southwest, Alaska Airlines and Delta from Denver to Illinois 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
4,411 reviews

Entertainment

7.6

Boarding

8.2

Overall

8.1

Comfort

8.1

Food

7.1

Crew

8.7

Reviews

1 / 20

2.0
Mediocre

Anonymous,Feb 2025

MCO - STL

Cancelled at last minute, SWA unable to assist in formulating alternate plans. Wound up renting a car and driving 13 hours to beat bad weather forecast at home. Not SWA’s fault that there was significant bad weather across the country.

Southwest
8.1
Very good
4,411 reviews
Southwest
8.1
Very good
4,411 reviews

Entertainment

7.6

Boarding

8.2

Overall

8.1

Comfort

8.1

Food

7.1

Crew

8.7

Reviews

1 / 20

2.0
Mediocre

Anonymous,Feb 2025

MCO - STL

Cancelled at last minute, SWA unable to assist in formulating alternate plans. Wound up renting a car and driving 13 hours to beat bad weather forecast at home. Not SWA’s fault that there was significant bad weather across the country.

Alaska Airlines
8.0
Very good
9,697 reviews
Southwest
8.1
Very good
4,411 reviews

Entertainment

7.6

Boarding

8.2

Overall

8.1

Comfort

8.1

Food

7.1

Crew

8.7

Reviews

1 / 20

2.0
Mediocre

Anonymous,Feb 2025

MCO - STL

Cancelled at last minute, SWA unable to assist in formulating alternate plans. Wound up renting a car and driving 13 hours to beat bad weather forecast at home. Not SWA’s fault that there was significant bad weather across the country.

Delta
8.0
Very good
8,219 reviews
Southwest
8.1
Very good
4,411 reviews

Entertainment

7.6

Boarding

8.2

Overall

8.1

Comfort

8.1

Food

7.1

Crew

8.7

Reviews

1 / 20

2.0
Mediocre

Anonymous,Feb 2025

MCO - STL

Cancelled at last minute, SWA unable to assist in formulating alternate plans. Wound up renting a car and driving 13 hours to beat bad weather forecast at home. Not SWA’s fault that there was significant bad weather across the country.

JetBlue
7.4
Good
3,070 reviews
Southwest
8.1
Very good
4,411 reviews

Entertainment

7.6

Boarding

8.2

Overall

8.1

Comfort

8.1

Food

7.1

Crew

8.7

Reviews

1 / 20

2.0
Mediocre

Anonymous,Feb 2025

MCO - STL

Cancelled at last minute, SWA unable to assist in formulating alternate plans. Wound up renting a car and driving 13 hours to beat bad weather forecast at home. Not SWA’s fault that there was significant bad weather across the country.

United Airlines
7.4
Good
8,765 reviews
Southwest
8.1
Very good
4,411 reviews

Entertainment

7.6

Boarding

8.2

Overall

8.1

Comfort

8.1

Food

7.1

Crew

8.7

Reviews

1 / 20

2.0
Mediocre

Anonymous,Feb 2025

MCO - STL

Cancelled at last minute, SWA unable to assist in formulating alternate plans. Wound up renting a car and driving 13 hours to beat bad weather forecast at home. Not SWA’s fault that there was significant bad weather across the country.

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.

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

    Most people fly from Denver Intl (DEN) if they book a flight from Denver to Illinois. Denver Intl is conveniently located just 18.5 mi from Denver’s city center.

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

    $31 is the cheapest one-way deal found within the past few days, from Frontier. You may also be able to find cheap deals on Southwest and United Airlines, with prices starting from $80 and $85, respectively.

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

    When deciding which route to take from Denver to Illinois consider Denver Intl - Chicago O'Hare Intl, Denver Intl - Chicago Midway or Denver Intl - Lambert-St Louis as they are the most popular.

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

    No one likes to see their flight delayed. When booking a flight from Denver to Illinois consider choosing Qatar Airways (93%), Royal Jordanian (89%) or British Airways (88%) as they are the most reliable in getting you off to your destination on time.

  • What are the cheapest flights from Denver to Illinois?

    Looking at all options, your cheapest flight can be booked for $81. While the most popular route (Denver Intl - Chicago O'Hare Intl) can be booked for $119 on average our data indicates $877 when flying from Denver to Illinois.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from Denver to Illinois 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 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.

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Alternative routes for Denver to Illinois

See prices for flight routes from nearby airports that may be better suited for you.
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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 février 20, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$42Average$142FlexibilityNo cancel feeOn-time62%
Allegiant AirCheapest$84Average$163FlexibilityNo cancel feeOn-time88%
American AirlinesCheapest$139Average$382FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$145Average$352FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$155Average$244FlexibilityNo cancel feeOn-time63%
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