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Cheap flights from Illinois to Denver from $80

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Illinois to Denver departing on 7/19. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
0 bags

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Find the cheapest flights from Illinois to Denver

Cheap round-trip flights

Enter your travel dates to find the best prices.
Frontier Logo
6:33 pm - 8:58 am
STL
-
DEN
15h 25m
1 stop
Frontier Logo
4:12 pm - 7:23 pm
DEN
-
STL
2h 11mnonstop
$133Frontier
Tue, Aug 18 - Tue, Aug 25
Frontier Logo
8:08 pm - 9:44 pm
STL
-
DEN
2h 36mnonstop
Frontier Logo
4:12 pm - 7:23 pm
DEN
-
STL
2h 11mnonstop
$137Frontier
Wed, Aug 19 - Sat, Aug 22
Frontier Logo
8:08 pm - 9:44 pm
STL
-
DEN
2h 36mnonstop
Frontier Logo
4:12 pm - 7:23 pm
DEN
-
STL
2h 11mnonstop
$138Frontier
Tue, Aug 18 - Thu, Aug 27
Allegiant Air Logo
11:07 am - 12:30 pm
PIA
-
DEN
2h 23mnonstop
Allegiant Air Logo
4:24 pm - 7:34 pm
DEN
-
PIA
2h 10mnonstop
$164Allegiant Air
Sun, Jul 19 - Thu, Jul 23
Allegiant Air Logo
5:23 pm - 6:48 pm
PIA
-
DEN
2h 25mnonstop
Allegiant Air Logo
4:27 pm - 7:37 pm
DEN
-
PIA
2h 10mnonstop
$201Allegiant Air
Thu, Aug 6 - Sun, Aug 9
Southwest Logo
5:30 am - 7:05 am
MDW
-
DEN
2h 35mnonstop
Southwest Logo
7:00 pm - 10:25 pm
DEN
-
MDW
2h 25mnonstop
$217Southwest
Wed, Jul 1 - Wed, Jul 8
United Airlines Logo
9:05 am - 10:34 am
MLI
-
DEN
2h 29mnonstop
United Airlines Logo
5:40 pm - 9:01 pm
DEN
-
MLI
2h 21mnonstop
$269United Airlines
Wed, Sep 9 - Wed, Sep 16
American Airlines Logo
6:43 pm - 12:17 am
CMI
-
DEN
6h 34m
1 stop
American Airlines Logo
7:13 am - 2:15 pm
DEN
-
CMI
6h 02m
1 stop
$270American Airlines
Tue, Jun 16 - Tue, Jun 23
United Airlines Logo
8:58 am - 10:28 am
MLI
-
DEN
2h 30mnonstop
United Airlines Logo
6:00 am - 1:56 pm
DEN
-
MLI
6h 56m
1 stop
$279United Airlines
Tue, Jun 16 - Sat, Jun 20
American Airlines Logo
6:43 pm - 12:17 am
CMI
-
DEN
6h 34m
1 stop
American Airlines Logo
6:22 am - 2:15 pm
DEN
-
CMI
6h 53m
1 stop
$306American Airlines
Tue, Jun 23 - Sat, Jun 27

Frontier flights from Illinois to Denver

Our best Frontier deals on Illinois to Denver flight tickets
Frontier
Aug 18
STL8:08 pmLambert-St Louis
2h 36m
DEN9:44 pmDenver Intl
Aug 26
DEN11:42 pmDenver Intl
16h 48m
1 stop
STL5:30 pmLambert-St Louis
$133
Frontier
Aug 19
STL8:08 pmLambert-St Louis
2h 36m
DEN9:44 pmDenver Intl
Aug 22
DEN4:12 pmDenver Intl
2h 11m
STL7:23 pmLambert-St Louis
$137
Frontier
Aug 18
STL8:08 pmLambert-St Louis
2h 36m
DEN9:44 pmDenver Intl
Aug 25
DEN6:30 amDenver Intl
10h 00m
1 stop
STL5:30 pmLambert-St Louis
$138

United Airlines flights from Illinois to Denver

Our best United Airlines deals on Illinois to Denver flight tickets
United Airlines
Sep 9
MLI9:05 amMoline Quad-City
2h 29m
DEN10:34 amDenver Intl
Sep 16
DEN5:40 pmDenver Intl
2h 21m
MLI9:01 pmMoline Quad-City
$269
United Airlines
Jun 16
MLI8:58 amMoline Quad-City
2h 30m
DEN10:28 amDenver Intl
Jun 20
DEN6:00 amDenver Intl
6h 56m
1 stop
MLI1:56 pmMoline Quad-City
$279
United Airlines
Oct 30
MLI5:42 pmMoline Quad-City
6h 21m
1 stop
DEN11:03 pmDenver Intl
Nov 2
DEN6:00 pmDenver Intl
2h 03m
MLI9:03 pmMoline Quad-City
$291

momondo 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, momondo users made 832,500 searches. Data last updated May 18, 2026.
Use the filters below to find and compare flights from Illinois to Denver that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Tue 8/18

6:33 pm-8:58 am

1 stop15h 25m

Denver Intl

Tue 8/25

4:12 pm-7:23 pm

Nonstop2h 11m

$133

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Wed 8/19

8:08 pm-9:44 pm

Nonstop2h 36m

Denver Intl

Sat 8/22

4:12 pm-7:23 pm

Nonstop2h 11m

$137

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Tue 8/18

8:08 pm-9:44 pm

Nonstop2h 36m

Denver Intl

Thu 8/27

4:12 pm-7:23 pm

Nonstop2h 11m

$138
Quickest round-trip

PeoriaDenver

PIA - DEN

PIADEN

Greater Peoria

Sun 7/19

11:07 am-12:30 pm

Nonstop2h 23m

Denver Intl

Thu 7/23

4:24 pm-7:34 pm

Nonstop2h 10m

$164

PeoriaDenver

PIA - DEN

PIADEN

Greater Peoria

Thu 8/6

5:23 pm-6:48 pm

Nonstop2h 25m

Denver Intl

Sun 8/9

4:27 pm-7:37 pm

Nonstop2h 10m

$201

ChicagoDenver

MDW - DEN

MDWDEN

Chicago Midway

Wed 7/1

5:30 am-7:05 am

Nonstop2h 35m

Denver Intl

Wed 7/8

7:00 pm-10:25 pm

Nonstop2h 25m

$217

MolineDenver

MLI - DEN

MLIDEN

Moline Quad-City

Wed 9/9

9:05 am-10:34 am

Nonstop2h 29m

Denver Intl

Wed 9/16

5:40 pm-9:01 pm

Nonstop2h 21m

$269

ChampaignDenver

CMI - DEN

CMIDEN

Champaign University-Willard

Tue 6/16

6:43 pm-12:17 am

1 stop6h 34m

Denver Intl

Tue 6/23

7:13 am-2:15 pm

1 stop6h 02m

$270

MolineDenver

MLI - DEN

MLIDEN

Moline Quad-City

Tue 6/16

8:58 am-10:28 am

Nonstop2h 30m

Denver Intl

Sat 6/20

6:00 am-1:56 pm

1 stop6h 56m

$279

ChampaignDenver

CMI - DEN

CMIDEN

Champaign University-Willard

Tue 6/23

6:43 pm-12:17 am

1 stop6h 34m

Denver Intl

Sat 6/27

6:22 am-2:15 pm

1 stop6h 53m

$306

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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How to get the cheapest flight ticket from Illinois to Denver

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 Denver?

The cheapest month to fly to Denver from Illinois is in October. Flight prices, which tend to average around $165, are often lower during this time because this is during the off-season. If you don’t want to visit Denver in October, then you should wait until November to fly from Illinois, when ticket prices are also cheap, with an average price of $183.

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

The cheapest day to depart on your flight to Denver is on a Saturday when prices can be found for as low as $248. This is often the case because there is less demand to fly during this day of the week. The most expensive day to fly to Denver is Monday, with ticket prices averaging around $302.

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

The cheapest time of day to fly to Denver is in the evening when flights can be purchased for as low as $239. Flights in the afternoon are often more expensive with an average ticket price of $284.

What is the cheapest Illinois to Denver Intl flight route?

Fly from Chicago O'Hare Intl to Denver Intl for the best Illinois - Denver Intl flight prices

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

You are more likely to see cheaper flights to Denver from Illinois when booking weeks ahead of your departure date. In general, you can expect to find flights to Denver for around $236 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Denver from Illinois for as low as $196 on momondo.

Can stopping save me money on Illinois to Denver flights?

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

Cheap Illinois to Denver flight deals and tips

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

Best Price Found

$132

Fastest flight time

2h 19m

Direct flights

Every day

Airports in Denver

1 airport
The best one-way flight to Denver from Illinois in the past 72 hours is $132. The best round-trip flight deal from Illinois to Denver found on momondo in the last 72 hours is $238.
The fastest flight from Illinois to Denver takes 2h 19m
Direct flights go from Illinois to Denver every day.
There is 1 airport in Denver. From Illinois there are direct flights to Denver Intl (DEN).
Search flight deals

Frequently asked questions about flying from Illinois to Denver

  • When did momondo last update prices for flights from Illinois to Denver Intl Airport?

    Prices for flights from Illinois to Denver Intl Airport are refreshed on a daily basis.

  • How many operators does momondo search for flights from Illinois to Denver Intl Airport?

  • How old do you have to be to fly from Illinois to Denver Intl Airport?

    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 Illinois to Denver Intl Airport.

  • What documentation or ID do you need to fly to Denver Intl Airport?

    The required travel and health documents for your Denver Intl Airport 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 Denver Intl Airport. 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 Illinois to Denver?

Best airlines flying from Illinois to Denver

Compare and see reviews for airlines that fly from Illinois to Denver with momondo
Airline
Rating
Free Cancellation
Price
Allegiant AirPriceFrom $51Free CancellationRating
7.3
709 reviews
Search Allegiant Air flights
FrontierPriceFrom $69Free CancellationRating
5.6
2,945 reviews
Search Frontier flights
DeltaPriceFrom $105Free CancellationRating
7.9
8,450 reviews
Search Delta flights
JetBluePriceFrom $145Free CancellationRating
7.2
2,982 reviews
Search JetBlue flights
SouthwestPriceFrom $151Free CancellationRating
7.9
4,284 reviews
Search Southwest flights
American AirlinesPriceFrom $153Free CancellationRating
7.1
11,645 reviews
Search American Airlines flights
United AirlinesPriceFrom $162Free CancellationRating
7.4
9,731 reviews
Search United Airlines flights

Traveling to a place near Denver?

Book flights to Denver if you plan to visit one of these locations
Breckenridge
Estes Park
Black Hawk
Aurora
Fort Collins
Manitou Springs
Boulder
Longmont
Greeley
Keystone
Lakewood
Westminster
Cripple Creek
Thornton
Frisco
Centennial
Englewood
Winter Park
Grand Lake
Copper Mountain

Why use momondo?

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

It is quick and easy to find Illinois to Denver flights on momondo. We search and return numerous flight options from various airlines and agents. You can then use our filters to narrow your search until you have found the most convenient flight to Denver that suits you.

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

Yes. momondo allows you to filter the results for Illinois to Denver flights to just show those with flexible booking policies.

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

momondo helps you find the best flight between Illinois and Denver by providing filters to narrow your choice of flights to those matching your criteria. You can select flights based on numerous factors such as price, departure and landing times, airport and airline.

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

Yes momondo offers price alerts on flights to Denver from Illinois. After performing a search on this page you should be able to see the price alert set up feature. Simply provide a valid email address and momondo will instantly alert you when prices change.

An easier way to manage your Denver trip

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