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Cheap flights from Illinois to Denver from $34

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 4/20. 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
8:08 pm - 9:41 pm
STL
-
DEN
2h 33mnonstop
Frontier Logo
4:15 pm - 7:23 pm
DEN
-
STL
2h 08mnonstop
$81Frontier
Sat, May 9 - Sat, May 16
Frontier Logo
8:08 pm - 9:41 pm
STL
-
DEN
2h 33mnonstop
Frontier Logo
4:15 pm - 7:23 pm
DEN
-
STL
2h 08mnonstop
$82Frontier
Sat, May 9 - Mon, May 11
Allegiant Air Logo
10:07 am - 11:26 am
PIA
-
DEN
2h 19mnonstop
Allegiant Air Logo
2:27 pm - 5:34 pm
DEN
-
PIA
2h 07mnonstop
$139Allegiant Air
Sun, Aug 23 - Thu, Aug 27
Multiple Airlines Logo
9:45 am - 5:48 pm
ORD
-
DEN
9h 03m
1 stop
Multiple Airlines Logo
3:07 pm - 11:21 am
DEN
-
ORD
19h 14m
1 stop
$158Multiple Airlines
Tue, Apr 14 - Wed, Apr 15
Southwest Logo
8:50 pm - 10:35 pm
MDW
-
DEN
2h 45mnonstop
Southwest Logo
6:35 am - 9:55 am
DEN
-
MDW
2h 20mnonstop
$159Southwest
Wed, May 6 - Wed, May 13
Southwest Logo
8:50 pm - 10:35 pm
MDW
-
DEN
2h 45mnonstop
Southwest Logo
11:05 am - 4:35 pm
DEN
-
MDW
4h 30m
1 stop
$165Southwest
Wed, May 6 - Tue, May 12
Allegiant Air Logo
10:07 am - 11:26 am
PIA
-
DEN
2h 19mnonstop
Allegiant Air Logo
2:27 pm - 5:34 pm
DEN
-
PIA
2h 07mnonstop
$203Allegiant Air
Thu, Aug 27 - Thu, Aug 27
Multiple Airlines Logo
4:24 pm - 10:39 pm
MLI
-
DEN
31h 15m
1 stop
Multiple Airlines Logo
10:29 pm - 11:39 am
DEN
-
MLI
12h 10m
1 stop
$246Multiple Airlines
Wed, May 27 - Wed, Jun 3
United Airlines Logo
8:50 am - 10:33 am
PIA
-
DEN
2h 43mnonstop
United Airlines Logo
5:55 pm - 9:19 pm
DEN
-
PIA
2h 24mnonstop
$269United Airlines
Sat, Apr 18 - Tue, Apr 21
United Airlines Logo
8:55 am - 10:33 am
MLI
-
DEN
2h 38mnonstop
United Airlines Logo
5:25 pm - 8:46 pm
DEN
-
MLI
2h 21mnonstop
$269United Airlines
Sat, May 2 - Wed, May 6

Frontier flights from Illinois to Denver

Our best Frontier deals on Illinois to Denver flight tickets
Frontier
May 9
STL8:08 pmLambert-St Louis
2h 33m
DEN9:41 pmDenver Intl
May 16
DEN4:15 pmDenver Intl
2h 08m
STL7:23 pmLambert-St Louis
$81
Frontier
May 9
STL8:08 pmLambert-St Louis
2h 33m
DEN9:41 pmDenver Intl
May 11
DEN4:15 pmDenver Intl
2h 08m
STL7:23 pmLambert-St Louis
$82
Frontier
May 4
STL8:17 pmLambert-St Louis
2h 33m
DEN9:50 pmDenver Intl
May 9
DEN4:15 pmDenver Intl
2h 08m
STL7:23 pmLambert-St Louis
$83

United Airlines flights from Illinois to Denver

Our best United Airlines deals on Illinois to Denver flight tickets
United Airlines
Apr 21
ORD2:35 pmChicago O'Hare Intl
2h 54m
DEN4:29 pmDenver Intl
Apr 30
DEN8:20 pmDenver Intl
2h 37m
ORD11:57 pmChicago O'Hare Intl
$175
United Airlines
Apr 23
ORD10:04 pmChicago O'Hare Intl
2h 55m
DEN11:59 pmDenver Intl
Apr 30
DEN8:20 pmDenver Intl
2h 37m
ORD11:57 pmChicago O'Hare Intl
$191
United Airlines
Apr 18
PIA8:50 amGreater Peoria
2h 43m
DEN10:33 amDenver Intl
Apr 21
DEN5:55 pmDenver Intl
2h 24m
PIA9:19 pmGreater Peoria
$269

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 March 31, 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

Sat 5/9

8:08 pm-9:41 pm

Nonstop2h 33m

Denver Intl

Sat 5/16

4:15 pm-7:23 pm

Nonstop2h 08m

$81

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Sat 5/9

8:08 pm-9:41 pm

Nonstop2h 33m

Denver Intl

Mon 5/11

4:15 pm-7:23 pm

Nonstop2h 08m

$82
Quickest round-trip

PeoriaDenver

PIA - DEN

PIADEN

Greater Peoria

Sun 8/23

10:07 am-11:26 am

Nonstop2h 19m

Denver Intl

Thu 8/27

2:27 pm-5:34 pm

Nonstop2h 07m

$139

ChicagoDenver

ORD - DEN

ORDDEN

Chicago O'Hare Intl

Tue 4/14

9:45 am-5:48 pm

1 stop9h 03m

Denver Intl

Wed 4/15

3:07 pm-11:21 am

1 stop19h 14m

$158

ChicagoDenver

MDW - DEN

MDWDEN

Chicago Midway

Wed 5/6

8:50 pm-10:35 pm

Nonstop2h 45m

Denver Intl

Wed 5/13

6:35 am-9:55 am

Nonstop2h 20m

$159

ChicagoDenver

MDW - DEN

MDWDEN

Chicago Midway

Wed 5/6

8:50 pm-10:35 pm

Nonstop2h 45m

Denver Intl

Tue 5/12

11:05 am-4:35 pm

1 stop4h 30m

$165

PeoriaDenver

PIA - DEN

PIADEN

Greater Peoria

Thu 8/27

10:07 am-11:26 am

Nonstop2h 19m

Denver Intl

Thu 8/27

2:27 pm-5:34 pm

Nonstop2h 07m

$203

MolineDenver

MLI - DEN

MLIDEN

Moline Quad-City

Wed 5/27

4:24 pm-10:39 pm

1 stop31h 15m

Denver Intl

Wed 6/3

10:29 pm-11:39 am

1 stop12h 10m

$246

PeoriaDenver

PIA - DEN

PIADEN

Greater Peoria

Sat 4/18

8:50 am-10:33 am

Nonstop2h 43m

Denver Intl

Tue 4/21

5:55 pm-9:19 pm

Nonstop2h 24m

$269

MolineDenver

MLI - DEN

MLIDEN

Moline Quad-City

Sat 5/2

8:55 am-10:33 am

Nonstop2h 38m

Denver Intl

Wed 5/6

5:25 pm-8:46 pm

Nonstop2h 21m

$269

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 $185, 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 $186.

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 $238. 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 $291.

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 $249. Flights at noon are often more expensive with an average ticket price of $272.

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 $226 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

$147

Fastest flight time

2h 15m

Direct flights

Every day

Airports in Denver

1 airport
The best one-way flight to Denver from Illinois in the past 72 hours is $147. The best round-trip flight deal from Illinois to Denver found on momondo in the last 72 hours is $232.
The fastest flight from Illinois to Denver takes 2h 15m
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 $55Free CancellationRating
7.3
709 reviews
Search Allegiant Air flights
FrontierPriceFrom $69Free CancellationRating
5.7
3,008 reviews
Search Frontier flights
JetBluePriceFrom $145Free CancellationRating
7.2
2,905 reviews
Search JetBlue flights
American AirlinesPriceFrom $152Free CancellationRating
7.1
11,542 reviews
Search American Airlines flights
SouthwestPriceFrom $156Free CancellationRating
8.0
4,334 reviews
Search Southwest flights
United AirlinesPriceFrom $158Free CancellationRating
7.4
9,530 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
Longmont
Boulder
Greeley
Keystone
Cripple Creek
Lakewood
Westminster
Thornton
Frisco
Centennial
Grand Lake
Winter Park
Englewood
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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