How long is the flight from Colorado to Illinois?

The flight from Colorado to Illinois depends on which airports you’re departing and arriving from and whether or not you have a layover. If you fly from Denver (a popular airport in Colorado) to Chicago O'Hare Intl Airport (the most popular airport in Illinois), then the flight time is 2h 23m on average. If you fly from Colorado Springs (another popular airport in Colorado) to Chicago O'Hare Intl Airport, then the average flight time is 2h 41m.

What is the cheapest airline that flies from Colorado to Illinois?

Frontier, United Airlines, and Southwest are the most popular carriers operating from Colorado to Illinois

How many flights depart from Colorado to Illinois on average per day?

As of August 2025, 83 flights take off from Colorado and land in Illinois each day. The most common flight departure time for this route is 2:00PM, with 49% of daily flights taking off in the afternoon.

What airlines fly to Illinois?

United Airlines, Frontier and American Airlines are the top three most popular airlines that fly to Illinois from Colorado according to our data. United Airlines is the first choice among our users, with 32% of people opting to fly with this airline when traveling to Illinois. Keep in mind that there are 5 different airlines that fly to Illinois on a routine basis, so you have a few additional options to choose from.

How many flights depart from Colorado to Illinois on average per week?

The number of flights available between Colorado and Illinois is 582 per week as of August 2025. The most frequent departure day is Thu, with 18% of weekly flights leaving on this day.

When did momondo last update prices for flights from Colorado to Illinois?

Prices for flights from Colorado to Illinois are updated daily.

How many operators does momondo search for flights from Colorado to Illinois?

As of August 2025, there are 5 operators available to choose from for flights from Colorado to Illinois.

How old do you have to be to fly from Colorado to Illinois?

The minimum age for a child to fly alone is five, but airlines that offer an unaccompanied minor (UNMR) service may have their own age limitations. Flight duration, scheduling, and layovers are among the considerations that may influence age limits. We recommend that you double-check with the airline you are booking with for travel from Colorado to Illinois.

What documentation or ID do you need to fly to Illinois?

The required travel and health documents for your Illinois trip may vary depending on your itinerary and personal circumstances. As a general rule, you should carry multiple documents, including a national ID card or driver's license and a passport valid for six months after your intended arrival at Illinois. We recommend that you seek guidance from your airline or a reliable third party such as IATA.

$59 Cheap Flights from Colorado to Illinois in 2025

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Find the cheapest flights from Colorado to Illinois

Round-trip

One-way

Last minute

Direct

Cheap round-trip flights

6:00 am - 9:06 amDEN-STL

2h 06mnonstop

7:55 pm - 9:20 pmSTL-DEN

2h 25mnonstop

$99Frontier

Find Deal

vie., sep. 12 - lun., sep. 22

6:00 am - 9:06 amDEN-STL

2h 06mnonstop

7:55 pm - 9:20 pmSTL-DEN

2h 25mnonstop

$100Frontier

Find Deal

mié., oct. 1 - lun., oct. 6

5:54 pm - 8:51 pmDEN-PIA

1h 57mnonstop

3:38 pm - 5:04 pmPIA-DEN

2h 26mnonstop

$130Allegiant Air

Find Deal

vie., ene. 2 - lun., ene. 5

8:45 pm - 12:05 amDEN-MDW

2h 20mnonstop

6:00 am - 7:35 amMDW-DEN

2h 35mnonstop

$160Southwest

Find Deal

jue., sep. 25 - mar., sep. 30

9:35 am - 3:50 pmDEN-MDW

5h 15m1 stop

8:30 am - 10:15 amMDW-DEN

2h 45mnonstop

$161Southwest

Find Deal

sáb., sep. 27 - sáb., oct. 4

6:41 pm - 9:32 pmDEN-PIA

1h 51mnonstop

11:59 am - 1:15 pmPIA-DEN

2h 16mnonstop

$177Allegiant Air

Find Deal

lun., oct. 13 - lun., oct. 20

5:52 pm - 9:05 pmDEN-PIA

2h 13mnonstop

8:39 am - 10:20 amPIA-DEN

2h 41mnonstop

$209United Airlines

Find Deal

vie., sep. 26 - dom., sep. 28

5:52 pm - 9:05 pmDEN-PIA

2h 13mnonstop

5:20 pm - 10:00 pmPIA-DEN

5h 40m1 stop

$219United Airlines

Find Deal

vie., sep. 26 - mar., sep. 30

12:59 pm - 4:45 pmCOS-ORD

2h 46mnonstop

10:02 am - 12:06 pmORD-COS

3h 04mnonstop

$227American Airlines

Find Deal

lun., nov. 17 - jue., nov. 20

12:13 pm - 3:57 pmCOS-ORD

2h 44mnonstop

9:45 am - 11:30 amORD-COS

2h 45mnonstop

$243American Airlines

Find Deal

jue., ene. 15 - lun., ene. 19

Frontier flights from Colorado to Illinois

Our best Frontier deals on Colorado to Illinois flight tickets

Frontier

Sep 9

DEN6:00 amDenver Intl

2h 06m

STL9:06 amLambert-St Louis

Sep 12

STL7:55 pmLambert-St Louis

2h 25m

DEN9:20 pmDenver Intl

$99

Find similar

Frontier

Oct 1

DEN6:00 amDenver Intl

2h 06m

STL9:06 amLambert-St Louis

Oct 6

STL7:55 pmLambert-St Louis

2h 25m

DEN9:20 pmDenver Intl

$100

Find similar

Frontier

Sep 15

DEN6:00 amDenver Intl

2h 06m

STL9:06 amLambert-St Louis

Sep 18

STL7:55 pmLambert-St Louis

2h 25m

DEN9:20 pmDenver Intl

$101

Find similar

American Airlines flights from Colorado to Illinois

Our best American Airlines deals on Colorado to Illinois flight tickets

American Airlines

Nov 17

COS12:59 pmColorado Springs

2h 46m

ORD4:45 pmChicago O'Hare Intl

Nov 20

ORD10:02 amChicago O'Hare Intl

3h 04m

COS12:06 pmColorado Springs

$227

Find similar

American Airlines

Jan 15

COS12:13 pmColorado Springs

2h 44m

ORD3:57 pmChicago O'Hare Intl

Jan 19

ORD9:45 amChicago O'Hare Intl

2h 45m

COS11:30 amColorado Springs

$243

Find similar

American Airlines

Nov 20

COS12:36 pmColorado Springs

2h 46m

ORD4:22 pmChicago O'Hare Intl

Nov 22

ORD6:51 pmChicago O'Hare Intl

5h 57m

1 stop

COS11:48 pmColorado Springs

$249

Find similar

Fly from

Fly to

Route

Depart

Return

Price

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

vie. 9/12

6:00 am-9:06 am

Nonstop2h 06m

Lambert-St Louis

lun. 9/22

7:55 pm-9:20 pm

Nonstop2h 25m

$99

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

mié. 10/1

6:00 am-9:06 am

Nonstop2h 06m

Lambert-St Louis

lun. 10/6

7:55 pm-9:20 pm

Nonstop2h 25m

$100

DenverPeoria

DEN - PIA

DENPIA

Denver Intl

vie. 1/2

5:54 pm-8:51 pm

Nonstop1h 57m

Greater Peoria

lun. 1/5

3:38 pm-5:04 pm

Nonstop2h 26m

$130

DenverChicago

DEN - MDW

DENMDW

Denver Intl

jue. 9/25

8:45 pm-12:05 am

Nonstop2h 20m

Chicago Midway

mar. 9/30

6:00 am-7:35 am

Nonstop2h 35m

$160

DenverChicago

DEN - MDW

DENMDW

Denver Intl

sáb. 9/27

9:35 am-3:50 pm

1 stop5h 15m

Chicago Midway

sáb. 10/4

8:30 am-10:15 am

Nonstop2h 45m

$161

DenverPeoria

DEN - PIA

DENPIA

Denver Intl

lun. 10/13

6:41 pm-9:32 pm

Nonstop1h 51m

Greater Peoria

lun. 10/20

11:59 am-1:15 pm

Nonstop2h 16m

$177

DenverPeoria

DEN - PIA

DENPIA

Denver Intl

vie. 9/26

5:52 pm-9:05 pm

Nonstop2h 13m

Greater Peoria

dom. 9/28

8:39 am-10:20 am

Nonstop2h 41m

$209

DenverPeoria

DEN - PIA

DENPIA

Denver Intl

vie. 9/26

5:52 pm-9:05 pm

Nonstop2h 13m

Greater Peoria

mar. 9/30

5:20 pm-10:00 pm

1 stop5h 40m

$219

Colorado SpringsChicago

COS - ORD

COSORD

Colorado Springs

lun. 11/17

12:59 pm-4:45 pm

Nonstop2h 46m

Chicago O'Hare Intl

jue. 11/20

10:02 am-12:06 pm

Nonstop3h 04m

$227

Colorado SpringsChicago

COS - ORD

COSORD

Colorado Springs

jue. 1/15

12:13 pm-3:57 pm

Nonstop2h 44m

Chicago O'Hare Intl

lun. 1/19

9:45 am-11:30 am

Nonstop2h 45m

$243

Flights are sorted by cheapest round-trip flights first.

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How to get the cheapest flight ticket from Colorado to Illinois

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

Prices

Airlines

Other information

What is the cheapest month to fly to Illinois?

The cheapest month to fly to Illinois from Colorado is in October. Flight prices, which tend to average around $161, are often lower during this time because this is during the off-season. If you aren’t able to travel to Illinois during the month of October, then flying in September is also cheap. Prices for this month can be found on momondo for an average of $164.

What is the cheapest day to depart on your flight to Illinois?

The cheapest day to depart from Colorado to Illinois is on a Friday when prices can be found for as low as $295. Flights from Colorado to Illinois on a Sunday will generally be more expensive and average around $498. Keep in mind that these prices on both days could fluctuate depending on the season and the demand.

What is the cheapest time of day to depart on your flight to Illinois?

Our most recent data shows that the best time of day to fly to Illinois is in the evening. Flights from Colorado to Illinois during this time can be as low as $192. Flights at noon are often more expensive with an average ticket price of $624.

What is the cheapest Colorado to Illinois flight route?

Fly from Denver Intl to Greater Peoria for the best Colorado - Illinois flight prices

How far in advance should I book a flight to Illinois?

You are more likely to see cheaper flights to Illinois from Colorado when booking weeks ahead of your departure date. In general, you can expect to find flights to Illinois for around $227 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Illinois from Colorado for as low as $189 on momondo.

What cabin class options are available on Colorado to Illinois flights?

There are 4 cabin classes available to choose from on Colorado to Illinois flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Can stopping save me money on Colorado to Illinois flights?

No. A direct flight is the cheapest option for a flight between Colorado to Illinois.

Cheap Colorado to Illinois flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Colorado to Illinois

Best Price Found	$79
Fastest flight time	1h 51m
Direct flights	Every day
Airports in Illinois	2 airports

The best one-way flight to Illinois from Colorado in the past 72 hours is $79. The best round-trip flight deal from Colorado to Illinois found on momondo in the last 72 hours is $113.

The fastest flight from Colorado to Illinois takes 1h 51m

Direct flights go from Colorado to Illinois every day.

There are 2 airports near Illinois: Greater Peoria (PIA), Lambert-St Louis (STL)

Search flight deals

When did momondo last update prices for flights from Colorado to Illinois?
Prices for flights from Colorado to Illinois are updated daily.
How many operators does momondo search for flights from Colorado to Illinois?
As of August 2025, there are 5 operators available to choose from for flights from Colorado to Illinois.
How old do you have to be to fly from Colorado to Illinois?
The minimum age for a child to fly alone is five, but airlines that offer an unaccompanied minor (UNMR) service may have their own age limitations. Flight duration, scheduling, and layovers are among the considerations that may influence age limits. We recommend that you double-check with the airline you are booking with for travel from Colorado to Illinois.
What documentation or ID do you need to fly to Illinois?
The required travel and health documents for your Illinois trip may vary depending on your itinerary and personal circumstances. As a general rule, you should carry multiple documents, including a national ID card or driver's license and a passport valid for six months after your intended arrival at Illinois. We recommend that you seek guidance from your airline or a reliable third party such as IATA.
What is the most popular plane model from Colorado to Illinois?
Based on momondo bookings for this flight route, the most popular plane model on flight routes from Colorado to Illinois is Boeing 737-800 Passenger/BBJ2 (winglets) (10.61% of total bookings). The next most popular plane models are Airbus A321neo (10.57%), Boeing 737-800 (10.32%), and Boeing 737 MAX 8 (9.65%).

Best airlines flying from Colorado to Illinois

Compare and see reviews for airlines that fly from Colorado to Illinois with momondo

Airline	Rating	Free Cancellation	Price
Frontier	PriceFrom $60	Free Cancellation	Rating 5.8 3,204 reviews	Search Frontier flights
Allegiant Air	PriceFrom $84	Free Cancellation	Rating 7.2 702 reviews	Search Allegiant Air flights
Southwest	PriceFrom $153	Free Cancellation	Rating 8.0 4,242 reviews	Search Southwest flights
American Airlines	PriceFrom $155	Free Cancellation	Rating 7.2 10,000 reviews	Search American Airlines flights
United Airlines	PriceFrom $166	Free Cancellation	Rating 7.4 8,944 reviews	Search United Airlines flights

Why use momondo?

Why should I use momondo to find a flight deal from Colorado to Illinois?

momondo compares prices from hundreds of airlines and agents so you can find and book the best deal on flights from Colorado to Illinois. Millions of users trust and use momondo every year so you are in good hands.

Can I find flights from Colorado to Illinois with flexible booking policies on momondo?

Flights from Colorado to Illinois with flexible booking policies can be found by using the search form above and then selecting our dedicated flexible booking filter, which will highlight only the flights where this policy is applied.

How can momondo help me find flights from Colorado to Illinois?

Once you have performed a search in the form on the page, momondo provides useful filters and insights. We can show you the cheapest days and times to fly as well as help filter your options to help you make an informed choice when booking flights to Illinois from Colorado.

I’m not ready to book a flight from Colorado to Illinois right now. Can momondo alert me if prices change?

If you are not ready to book a flight from Colorado to Illinois now, use our insights above to find helpful tips or alternatively set up a price alert, where momondo will track prices on flights to Illinois and let you know when they change.

An easier way to manage your Illinois trip

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Find better results for your trip to Illinois

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Cheap flights from Colorado to Illinois from $59

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Colorado to Illinois departing on 9/28. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.

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Big names and deals

Filter for what you want

Filter for what you want

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Find the cheapest flights from Colorado to Illinois

Cheap round-trip flights

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Cheap last minute flights

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Frontier flights from Colorado to Illinois

Our best Frontier deals on Colorado to Illinois flight tickets

American Airlines flights from Colorado to Illinois

Our best American Airlines deals on Colorado to Illinois flight tickets

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Use the filters below to find and compare flights from Colorado to Illinois that are best for you.

See travel insights to Illinois from

How to get the cheapest flight ticket from Colorado to Illinois

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the cheapest month to fly to Illinois?

What is the cheapest day to depart on your flight to Illinois?

What is the cheapest time of day to depart on your flight to Illinois?

Our most recent data shows that the best time of day to fly to Illinois is in the evening. Flights from Colorado to Illinois during this time can be as low as $192. Flights at noon are often more expensive with an average ticket price of $624.

What is the cheapest Colorado to Illinois flight route?

Fly from Denver Intl to Greater Peoria for the best Colorado - Illinois flight prices

How far in advance should I book a flight to Illinois?

What cabin class options are available on Colorado to Illinois flights?

There are 4 cabin classes available to choose from on Colorado to Illinois flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Can stopping save me money on Colorado to Illinois flights?

No. A direct flight is the cheapest option for a flight between Colorado to Illinois.

What is the cheapest airline that flies from Colorado to Illinois?

Frontier, United Airlines, and Southwest are the most popular carriers operating from Colorado to Illinois

What airlines fly to Illinois?

How many flights depart from Colorado to Illinois on average per day?

As of August 2025, 83 flights take off from Colorado and land in Illinois each day. The most common flight departure time for this route is 2:00PM, with 49% of daily flights taking off in the afternoon.

How many flights depart from Colorado to Illinois on average per week?

The number of flights available between Colorado and Illinois is 582 per week as of August 2025. The most frequent departure day is Thu, with 18% of weekly flights leaving on this day.

How long is the flight from Colorado to Illinois?

Cheap Colorado to Illinois flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Colorado to Illinois

Best Price Found

Fastest flight time

Direct flights

Airports in Illinois

When did momondo last update prices for flights from Colorado to Illinois?

How many operators does momondo search for flights from Colorado to Illinois?

How old do you have to be to fly from Colorado to Illinois?

What documentation or ID do you need to fly to Illinois?

What is the most popular plane model from Colorado to Illinois?

Best airlines flying from Colorado to Illinois

Compare and see reviews for airlines that fly from Colorado to Illinois with momondo

Why use momondo?

Why should I use momondo to find a flight deal from Colorado to Illinois?

Can I find flights from Colorado to Illinois with flexible booking policies on momondo?

How can momondo help me find flights from Colorado to Illinois?

I’m not ready to book a flight from Colorado to Illinois right now. Can momondo alert me if prices change?

An easier way to manage your Illinois trip

We make it super easy to schedule, organize and travel with friends or family. Trips is free — and available to use no matter where you book.

Get notified when prices go down

Daily price changes in your inbox - only with Price Alerts.

Find better results for your trip to Illinois

Popular cities in Illinois

Popular flights according to clicks in the last 7 days on momondo