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$28+ 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 1/22. Fares are subject to change and may not be available on all flights or dates of travel.
DEN — ORD
Jan 21 — Jan 281
Tue 1/21
Tue 1/28
1 adult, Economy
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Cheap flight deals from Denver to Illinois

Discover tips and strategies to find the most affordable flight options for your journey from Denver (DEN) to Illinois (USIL). 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 January 16, 2025.

Round-trip from

$67
(Cheapflightsfares)

One-way from

$28
(Cheapflightsfares)
From Denver Intl to Illinois
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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 January 16, 2025.

This Cheapflightsfares deal was found by Cheapflights users on 1/16. 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 2/56:00 amDEN - STL
Nonstop2h 16mFrontier
Fri 2/77:09 pmSTL - DEN
Nonstop2h 28mFrontier
Deal found 1/16$67
This Mytrip deal was found by Cheapflights users on 1/15. 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.
Mon 2/101:33 pmDEN - PIA
Nonstop2h 05mAllegiant Air
Mon 2/243:14 pmPIA - DEN
Nonstop2h 31mAllegiant Air
Deal found 1/15$87
This Frontier deal was found by Cheapflights users on 1/15. 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 2/151:52 pmDEN - ORD
Nonstop2h 33mFrontier
Mon 2/246:50 amORD - DEN
Nonstop3h 03mFrontier
Deal found 1/15$89
This Frontier deal was found by Cheapflights users on 1/15. 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 2/158:55 pmDEN - MDW
Nonstop2h 22mFrontier
Sun 2/236:40 amMDW - DEN
Nonstop2h 52mFrontier
Deal found 1/15$89
This Mytrip deal was found by Cheapflights users on 1/15. 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 2/151:52 pmDEN - ORD
Nonstop2h 33mMultiple Airlines
Sun 2/166:50 amORD - DEN
1 stop12h 13mMultiple Airlines
Deal found 1/15$163
This Southwest deal was found by Cheapflights users on 1/16. 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 2/154:10 pmDEN - ORD
Nonstop2h 30mSouthwest
Sun 2/166:15 amORD - DEN
Nonstop2h 45mSouthwest
Deal found 1/16$168
This Southwest deal was found by Cheapflights users on 1/15. 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 2/156:00 pmDEN - MDW
Nonstop2h 25mSouthwest
Sun 2/165:20 amMDW - DEN
Nonstop2h 55mSouthwest
Deal found 1/15$168
This American Airlines deal was found by Cheapflights users on 1/14. 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 2/157:00 amDEN - ORD
Nonstop2h 23mAmerican Airlines
Sun 2/168:40 pmORD - DEN
Nonstop3h 02mAmerican Airlines
Deal found 1/14$169
This United Airlines deal was found by Cheapflights users on 1/15. 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 2/186:00 amDEN - ORD
Nonstop2h 34mUnited Airlines
Tue 2/182:35 pmORD - DEN
Nonstop2h 53mUnited Airlines
Deal found 1/15$199
This Delta deal was found by Cheapflights users on 1/16. 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.
Thu 2/63:30 pmDEN - MLI
1 stop6h 08mDelta
Sun 2/95:05 pmMLI - DEN
1 stop6h 41mDelta
Deal found 1/16$209
This United Airlines deal was found by Cheapflights users on 1/16. 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 2/217:47 amDEN - STL
1 stop5h 49mUnited Airlines
Mon 2/245:36 pmSTL - DEN
1 stop6h 54mUnited Airlines
Deal found 1/16$217
This Delta deal was found by Cheapflights users on 1/16. 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 4/812:55 amDEN - MDW
1 stop7h 12mDelta
Sat 4/126:00 amMDW - DEN
1 stop7h 27mDelta
Deal found 1/16$221

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 January 16, 2025.

Fly from

Any airport

Fly to

Any airport

Route

Depart

Return

Price

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Wed 2/5

6:00 am-9:16 am

Nonstop2h 16m

Lambert-St Louis

Fri 2/7

7:09 pm-8:37 pm

Nonstop2h 28m

$67

DenverPeoria

DEN - PIA

DENPIA

Denver Intl

Mon 2/10

1:33 pm-4:38 pm

Nonstop2h 05m

Greater Peoria

Mon 2/24

3:14 pm-4:45 pm

Nonstop2h 31m

$87

DenverChicago

DEN - ORD

DENORD

Denver Intl

Sat 2/15

1:52 pm-5:25 pm

Nonstop2h 33m

Chicago O'Hare Intl

Mon 2/24

6:50 am-8:53 am

Nonstop3h 03m

$89

DenverChicago

DEN - MDW

DENMDW

Denver Intl

Wed 2/5

8:55 pm-12:17 am

Nonstop2h 22m

Chicago Midway

Mon 2/10

7:15 am-9:09 am

Nonstop2h 54m

$89

DenverChicago

DEN - ORD

DENORD

Denver Intl

Sat 2/15

1:52 pm-5:25 pm

Nonstop2h 33m

Chicago O'Hare Intl

Sun 2/16

6:50 am-6:03 pm

1 stop12h 13m

$163

DenverChicago

DEN - ORD

DENORD

Denver Intl

Sat 2/15

6:20 am-10:00 am

Nonstop2h 40m

Chicago O'Hare Intl

Sun 2/16

7:45 pm-9:40 pm

Nonstop2h 55m

$168

DenverChicago

DEN - MDW

DENMDW

Denver Intl

Sat 2/15

5:40 am-9:05 am

Nonstop2h 25m

Chicago Midway

Sun 2/16

5:20 am-7:15 am

Nonstop2h 55m

$168

DenverChicago

DEN - ORD

DENORD

Denver Intl

Sat 2/15

7:00 am-10:23 am

Nonstop2h 23m

Chicago O'Hare Intl

Sun 2/16

8:40 pm-10:42 pm

Nonstop3h 02m

$169

DenverChicago

DEN - ORD

DENORD

Denver Intl

Tue 2/18

6:00 am-9:34 am

Nonstop2h 34m

Chicago O'Hare Intl

Tue 2/18

2:35 pm-4:28 pm

Nonstop2h 53m

$199

DenverMoline

DEN - MLI

DENMLI

Denver Intl

Thu 2/6

3:30 pm-10:38 pm

1 stop6h 08m

Moline Quad-City

Sun 2/9

5:05 pm-10:46 pm

1 stop6h 41m

$209

Flights are sorted by cheapest round-trip flights first.

Deals found on 1/16

Showing 1-10 of 58 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 $320). 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 January 16, 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 January 16, 2025.

The most flights from DEN to USIL are scheduled on a Monday (45 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (19 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 January 16, 2025.
Get a feel of what it's like to fly with Delta, Southwest and American Airlines 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
4,659 reviews

Entertainment

7.7

Boarding

8.2

Comfort

8.1

Crew

8.7

Food

7.2

Overall

8.1

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Southwest
8.1
Very good
4,659 reviews
Southwest
8.1
Very good
4,659 reviews

Entertainment

7.7

Boarding

8.2

Comfort

8.1

Crew

8.7

Food

7.2

Overall

8.1

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Alaska Airlines
8.0
Very good
9,681 reviews
Southwest
8.1
Very good
4,659 reviews

Entertainment

7.7

Boarding

8.2

Comfort

8.1

Crew

8.7

Food

7.2

Overall

8.1

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Delta
8.0
Very good
8,511 reviews
Southwest
8.1
Very good
4,659 reviews

Entertainment

7.7

Boarding

8.2

Comfort

8.1

Crew

8.7

Food

7.2

Overall

8.1

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

United Airlines
7.4
Good
8,965 reviews
Southwest
8.1
Very good
4,659 reviews

Entertainment

7.7

Boarding

8.2

Comfort

8.1

Crew

8.7

Food

7.2

Overall

8.1

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Allegiant Air
7.4
Good
801 reviews
Southwest
8.1
Very good
4,659 reviews

Entertainment

7.7

Boarding

8.2

Comfort

8.1

Crew

8.7

Food

7.2

Overall

8.1

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

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?

    $28 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 $70 and $80, 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 Japan Airlines (100%), Royal Jordanian (93%) or Cathay Pacific (91%) 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 $80. While the most popular route (Denver Intl - Chicago O'Hare Intl) can be booked for $92 on average our data indicates $1,326 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 $320). 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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Denver to Jacksonville flights
Denver to Sarasota flights

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 January 16, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$40Average$144FlexibilityNo cancel feeOn-time62%
Allegiant AirCheapest$90Average$166FlexibilityNo cancel feeOn-time88%
American AirlinesCheapest$139Average$374FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$141Average$372FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$154Average$244FlexibilityNo cancel feeOn-time63%
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