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Cheap flights from Illinois to Denver from $64

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 3/4. 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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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
8:12 pm - 9:49 pm
STL
-
DEN
2h 37mnonstop
Frontier Logo
6:35 am - 9:49 am
DEN
-
STL
2h 14mnonstop
$71Frontier
Sat, Mar 7 - Wed, Mar 11
Frontier Logo
8:12 pm - 9:45 pm
STL
-
DEN
2h 33mnonstop
Frontier Logo
4:00 pm - 7:12 pm
DEN
-
STL
2h 12mnonstop
$72Frontier
Fri, May 1 - Sat, May 2
Allegiant Air Logo
5:13 pm - 6:36 pm
PIA
-
DEN
2h 23mnonstop
Allegiant Air Logo
4:27 pm - 7:30 pm
DEN
-
PIA
2h 03mnonstop
$202Allegiant Air
Thu, May 21 - Thu, May 28
Multiple Airlines Logo
9:55 pm - 9:43 am
MLI
-
DEN
12h 48m
1 stop
Multiple Airlines Logo
10:40 pm - 9:05 pm
DEN
-
MLI
21h 25m
1 stop
$207Multiple Airlines
Fri, May 1 - Thu, May 7
United Airlines Logo
8:54 am - 10:33 am
MLI
-
DEN
2h 39mnonstop
United Airlines Logo
6:10 pm - 9:32 pm
DEN
-
MLI
2h 22mnonstop
$209United Airlines
Thu, Apr 16 - Tue, Apr 21
Multiple Airlines Logo
9:55 pm - 9:43 am
MLI
-
DEN
12h 48m
1 stop
Multiple Airlines Logo
10:40 pm - 9:05 pm
DEN
-
MLI
21h 25m
1 stop
$214Multiple Airlines
Fri, May 1 - Thu, May 7
United Airlines Logo
9:00 am - 10:05 am
PIA
-
DEN
2h 05mnonstop
United Airlines Logo
3:10 pm - 9:21 pm
DEN
-
PIA
5h 11m
1 stop
$219United Airlines
Wed, Mar 4 - Wed, Mar 11
Allegiant Air Logo
11:07 am - 12:34 pm
PIA
-
DEN
2h 27mnonstop
Allegiant Air Logo
4:50 pm - 7:56 pm
DEN
-
PIA
2h 06mnonstop
$220Allegiant Air
Thu, Jun 4 - Thu, Jun 11
American Airlines Logo
5:22 pm - 11:54 pm
PIA
-
DEN
7h 32m
1 stop
American Airlines Logo
7:00 am - 12:47 pm
DEN
-
PIA
4h 47m
1 stop
$229American Airlines
Thu, Mar 12 - Wed, Mar 18
American Airlines Logo
11:16 am - 5:02 pm
BMI
-
DEN
6h 46m
1 stop
American Airlines Logo
6:11 am - 2:16 pm
DEN
-
BMI
7h 05m
1 stop
$268American Airlines
Sat, May 16 - Wed, May 20

American Airlines flights from Illinois to Denver

Our best American Airlines deals on Illinois to Denver flight tickets
American Airlines
Mar 12
PIA5:22 pmGreater Peoria
7h 32m
1 stop
DEN11:54 pmDenver Intl
Mar 18
DEN7:00 amDenver Intl
4h 47m
1 stop
PIA12:47 pmGreater Peoria
$229
American Airlines
Apr 10
PIA5:40 pmGreater Peoria
7h 05m
1 stop
DEN11:45 pmDenver Intl
Apr 11
DEN6:11 amDenver Intl
5h 41m
1 stop
PIA12:52 pmGreater Peoria
$268
American Airlines
Feb 20
MLI1:30 pmMoline Quad-City
4h 47m
1 stop
DEN5:17 pmDenver Intl
Feb 23
DEN4:43 pmDenver Intl
5h 45m
1 stop
MLI11:28 pmMoline Quad-City
$339

Frontier flights from Illinois to Denver

Our best Frontier deals on Illinois to Denver flight tickets
Frontier
Mar 7
STL8:12 pmLambert-St Louis
2h 37m
DEN9:49 pmDenver Intl
Mar 11
DEN6:35 amDenver Intl
2h 14m
STL9:49 amLambert-St Louis
$71
Frontier
Mar 7
STL8:12 pmLambert-St Louis
2h 37m
DEN9:49 pmDenver Intl
Mar 11
DEN6:35 amDenver Intl
2h 14m
STL9:49 amLambert-St Louis
$77
Frontier
Mar 2
STL1:54 pmLambert-St Louis
2h 36m
DEN3:30 pmDenver Intl
Mar 9
DEN6:35 amDenver Intl
2h 14m
STL9:49 amLambert-St Louis
$85

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 February 11, 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

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Sat 3/7

8:12 pm-9:49 pm

Nonstop2h 37m

Denver Intl

Wed 3/11

6:35 am-9:49 am

Nonstop2h 14m

$71

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Fri 5/1

8:12 pm-9:45 pm

Nonstop2h 33m

Denver Intl

Sat 5/2

4:00 pm-7:12 pm

Nonstop2h 12m

$72

PeoriaDenver

PIA - DEN

PIADEN

Greater Peoria

Thu 5/21

5:13 pm-6:36 pm

Nonstop2h 23m

Denver Intl

Thu 5/28

4:27 pm-7:30 pm

Nonstop2h 03m

$202

MolineDenver

MLI - DEN

MLIDEN

Moline Quad-City

Fri 5/1

9:55 pm-9:43 am

1 stop12h 48m

Denver Intl

Thu 5/7

10:40 pm-9:05 pm

1 stop21h 25m

$207

MolineDenver

MLI - DEN

MLIDEN

Moline Quad-City

Thu 4/16

8:54 am-10:33 am

Nonstop2h 39m

Denver Intl

Tue 4/21

6:10 pm-9:32 pm

Nonstop2h 22m

$209

MolineDenver

MLI - DEN

MLIDEN

Moline Quad-City

Fri 5/1

9:55 pm-9:43 am

1 stop12h 48m

Denver Intl

Thu 5/7

10:40 pm-9:05 pm

1 stop21h 25m

$214

PeoriaDenver

PIA - DEN

PIADEN

Greater Peoria

Wed 3/4

9:00 am-10:05 am

Nonstop2h 05m

Denver Intl

Wed 3/11

3:10 pm-9:21 pm

1 stop5h 11m

$219

PeoriaDenver

PIA - DEN

PIADEN

Greater Peoria

Thu 6/4

11:07 am-12:34 pm

Nonstop2h 27m

Denver Intl

Thu 6/11

4:50 pm-7:56 pm

Nonstop2h 06m

$220

PeoriaDenver

PIA - DEN

PIADEN

Greater Peoria

Thu 3/12

5:22 pm-11:54 pm

1 stop7h 32m

Denver Intl

Wed 3/18

7:00 am-12:47 pm

1 stop4h 47m

$229

BloomingtonDenver

BMI - DEN

BMIDEN

Bloomington-Normal

Sat 5/16

11:16 am-5:02 pm

1 stop6h 46m

Denver Intl

Wed 5/20

6:11 am-2:16 pm

1 stop7h 05m

$268

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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See travel insights to Denver from

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 $183, 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 September to fly from Illinois, when ticket prices are also cheap, with an average price of $187.

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 $232. 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 Sunday, with ticket prices averaging around $275.

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 morning when flights can be purchased for as low as $241. Flights at noon are often more expensive with an average ticket price of $270.

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 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 $223 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 $187 on momondo.

What cabin class options are available on Illinois to Denver Intl flights?

There are 4 cabin classes available to choose from on Illinois to Denver Intl 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 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

$128

Fastest flight time

2h 05m

Direct flights

Every day

Airports in Denver

1 airport
The best one-way flight to Denver from Illinois in the past 72 hours is $128. The best round-trip flight deal from Illinois to Denver found on momondo in the last 72 hours is $208.
The fastest flight from Illinois to Denver takes 2h 05m
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

  • 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 $56Free CancellationRating
7.2
711 reviews
Search Allegiant Air flights
FrontierPriceFrom $58Free CancellationRating
5.7
3,052 reviews
Search Frontier flights
JetBluePriceFrom $145Free CancellationRating
7.2
2,896 reviews
Search JetBlue flights
American AirlinesPriceFrom $154Free CancellationRating
7.2
11,272 reviews
Search American Airlines flights
United AirlinesPriceFrom $155Free CancellationRating
7.4
9,282 reviews
Search United Airlines flights
SouthwestPriceFrom $157Free CancellationRating
8.0
4,282 reviews
Search Southwest 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
Cripple Creek
Longmont
Keystone
Greeley
Lakewood
Westminster
Thornton
Frisco
Copper Mountain
Winter Park
Centennial
Grand Lake
Englewood

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.

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