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Cheap flights from Denver to Illinois 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 Denver to Illinois departing on 9/24. 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
1 adult, Economy, 0 bags

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Find the cheapest flights from Denver to Illinois

Cheap round-trip flights

Enter your travel dates to find the best prices.
Allegiant Air Logo
10:20 am - 1:19 pm
DEN
-
PIA
1h 59mnonstop
Allegiant Air Logo
5:24 pm - 6:44 pm
PIA
-
DEN
2h 20mnonstop
$125Allegiant Air
Thu, Oct 29 - Sun, Nov 1
Allegiant Air Logo
2:16 pm - 5:19 pm
DEN
-
PIA
2h 03mnonstop
Allegiant Air Logo
10:07 am - 11:27 am
PIA
-
DEN
2h 20mnonstop
$144Allegiant Air
Thu, Sep 10 - Sun, Sep 13
Frontier Logo
5:05 am - 2:56 pm
DEN
-
STL
8h 51m
1 stop
Frontier Logo
7:58 pm - 9:25 pm
STL
-
DEN
2h 27mnonstop
$166Frontier
Sat, Aug 15 - Mon, Aug 24
Frontier Logo
6:30 am - 5:22 pm
DEN
-
STL
9h 52m
1 stop
Frontier Logo
7:58 pm - 9:25 pm
STL
-
DEN
2h 27mnonstop
$167Frontier
Thu, Sep 3 - Sun, Sep 6
Southwest Logo
8:25 pm - 11:45 pm
DEN
-
MDW
2h 20mnonstop
Southwest Logo
8:15 pm - 9:50 pm
MDW
-
DEN
2h 35mnonstop
$205Southwest
Thu, Sep 10 - Mon, Sep 14
Southwest Logo
4:55 pm - 8:15 pm
DEN
-
MDW
2h 20mnonstop
Southwest Logo
8:15 pm - 9:50 pm
MDW
-
DEN
2h 35mnonstop
$210Southwest
Fri, Sep 11 - Mon, Sep 14
United Airlines Logo
6:00 am - 12:22 pm
DEN
-
MLI
5h 22m
1 stop
United Airlines Logo
9:05 am - 10:34 am
MLI
-
DEN
2h 29mnonstop
$279United Airlines
Wed, Aug 12 - Wed, Aug 19
American Airlines Logo
6:41 am - 1:59 pm
DEN
-
CMI
6h 18m
1 stop
American Airlines Logo
7:11 am - 12:20 pm
CMI
-
DEN
6h 09m
1 stop
$280American Airlines
Wed, Nov 4 - Sat, Nov 7
American Airlines Logo
7:33 am - 1:59 pm
DEN
-
CMI
5h 26m
1 stop
American Airlines Logo
3:21 pm - 10:54 pm
CMI
-
DEN
8h 33m
2 stops
$286American Airlines
Wed, Nov 4 - Sat, Nov 7
United Airlines Logo
5:40 pm - 9:01 pm
DEN
-
MLI
2h 21mnonstop
United Airlines Logo
5:40 am - 10:32 am
MLI
-
DEN
5h 52m
1 stop
$289United Airlines
Fri, Aug 28 - Sun, Aug 30

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Frontier flights from Denver to Illinois

Our best Frontier deals on Denver to Illinois flight tickets
Frontier
Aug 15
DEN5:05 amDenver Intl
8h 51m
1 stop
STL2:56 pmLambert-St Louis
Aug 24
STL7:58 pmLambert-St Louis
2h 27m
DEN9:25 pmDenver Intl
$166
Frontier
Sep 3
DEN6:30 amDenver Intl
9h 52m
1 stop
STL5:22 pmLambert-St Louis
Sep 6
STL7:58 pmLambert-St Louis
2h 27m
DEN9:25 pmDenver Intl
$167
Frontier
Sep 11
DEN4:12 pmDenver Intl
2h 03m
STL7:15 pmLambert-St Louis
Sep 13
STL10:35 amLambert-St Louis
12h 58m
1 stop
DEN10:33 pmDenver Intl
$168

United Airlines flights from Denver to Illinois

Our best United Airlines deals on Denver to Illinois flight tickets
United Airlines
Aug 13
DEN7:10 pmDenver Intl
2h 36m
ORD10:46 pmChicago O'Hare Intl
Aug 15
ORD9:30 pmChicago O'Hare Intl
2h 53m
DEN11:23 pmDenver Intl
$205
United Airlines
Aug 12
DEN6:00 amDenver Intl
5h 22m
1 stop
MLI12:22 pmMoline Quad-City
Aug 19
MLI9:05 amMoline Quad-City
2h 29m
DEN10:34 amDenver Intl
$279
United Airlines
Aug 3
DEN5:38 pmDenver Intl
2h 16m
MLI8:54 pmMoline Quad-City
Aug 11
MLI10:30 amMoline Quad-City
5h 01m
1 stop
DEN2:31 pmDenver Intl
$312

momondo Fare Finder

 
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, momondo users made 832,500 searches. Data last updated July 25, 2026.
Use the filters below to find and compare flights from Denver to Illinois that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip
Quickest round-trip

DenverPeoria

DEN - PIA

DENPIA

Denver Intl

Thu 10/29

10:20 am-1:19 pm

Nonstop1h 59m

Greater Peoria

Sun 11/1

5:24 pm-6:44 pm

Nonstop2h 20m

$125

DenverPeoria

DEN - PIA

DENPIA

Denver Intl

Thu 9/10

2:16 pm-5:19 pm

Nonstop2h 03m

Greater Peoria

Sun 9/13

10:07 am-11:27 am

Nonstop2h 20m

$144

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Sat 8/15

5:05 am-2:56 pm

1 stop8h 51m

Lambert-St Louis

Mon 8/24

7:58 pm-9:25 pm

Nonstop2h 27m

$166

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Thu 9/3

6:30 am-5:22 pm

1 stop9h 52m

Lambert-St Louis

Sun 9/6

7:58 pm-9:25 pm

Nonstop2h 27m

$167

DenverChicago

DEN - MDW

DENMDW

Denver Intl

Thu 9/10

8:25 pm-11:45 pm

Nonstop2h 20m

Chicago Midway

Mon 9/14

8:15 pm-9:50 pm

Nonstop2h 35m

$205

DenverChicago

DEN - MDW

DENMDW

Denver Intl

Fri 9/11

4:55 pm-8:15 pm

Nonstop2h 20m

Chicago Midway

Mon 9/14

8:15 pm-9:50 pm

Nonstop2h 35m

$210

DenverMoline

DEN - MLI

DENMLI

Denver Intl

Wed 8/12

6:00 am-12:22 pm

1 stop5h 22m

Moline Quad-City

Wed 8/19

9:05 am-10:34 am

Nonstop2h 29m

$279

DenverChampaign

DEN - CMI

DENCMI

Denver Intl

Wed 11/4

6:41 am-1:59 pm

1 stop6h 18m

Champaign University-Willard

Sat 11/7

7:11 am-12:20 pm

1 stop6h 09m

$280

DenverChampaign

DEN - CMI

DENCMI

Denver Intl

Wed 11/4

7:33 am-1:59 pm

1 stop5h 26m

Champaign University-Willard

Sat 11/7

3:21 pm-10:54 pm

2 stops8h 33m

$286

DenverMoline

DEN - MLI

DENMLI

Denver Intl

Fri 8/28

5:40 pm-9:01 pm

Nonstop2h 21m

Moline Quad-City

Sun 8/30

5:40 am-10:32 am

1 stop5h 52m

$289

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 Illinois from

How to get the cheapest flight ticket from Denver 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?

The cheapest month to fly to Illinois from Denver is in January. Flight prices, which tend to average around $237, 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 January, then flying in September is also cheap. Prices for this month can be found on momondo for an average of $239.

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

The cheapest day to depart from Denver to Illinois is on a Friday when prices can be found for as low as $319. Flights from Denver to Illinois on a Sunday will generally be more expensive and average around $521. 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 Denver to Illinois during this time can be as low as $250. Flights at noon are often more expensive with an average ticket price of $534.

What is the cheapest Denver Intl to Illinois flight route?

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

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

You are more likely to see cheaper flights to Illinois from Denver when booking weeks ahead of your departure date. In general, you can expect to find flights to Illinois for around $288 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Illinois from Denver for as low as $238 on momondo.

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

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

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

Cheap Denver to Illinois flight deals and tips

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

Best Price Found

$140

Fastest flight time

1h 56m

Direct flights

Every day

Airports in Illinois

98 airports
The best one-way flight to Illinois from Denver in the past 72 hours is $140. The best round-trip flight deal from Denver to Illinois found on momondo in the last 72 hours is $261.
The fastest flight from Denver to Illinois takes 1h 56m
Direct flights go from Denver to Illinois every day.
There are 98 airports in Illinois. From Denver there are direct flights to Greater Peoria (PIA), Lambert-St Louis (STL), Moline Quad-City (MLI).
Search flight deals

Frequently asked questions about flying from Denver to Illinois

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

    Prices for flights from Denver Intl Airport to Illinois are updated daily.

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

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

    The minimum age for a child to fly alone is five, but airlines offering an unaccompanied minor (UNMR) service may have their age restrictions, such as regulations concerning flight duration, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Denver Intl Airport to Illinois.

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

    The travel and health documents you'll need for your trip to Illinois may differ based on your itinerary and personal situation. Typically, you should have several documents on hand, such as a national ID card or driver's license and a passport that is valid for six months after your intended arrival at Illinois. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.

  • What is the most popular plane model from Denver to Illinois?

Best airlines flying from Denver to Illinois

Compare and see reviews for airlines that fly from Denver to Illinois with momondo
Airline
Rating
Free Cancellation
Price
FrontierPriceFrom $77Free CancellationRating
5.6
2,771 reviews
Search Frontier flights
Allegiant AirPriceFrom $91Free CancellationRating
7.3
681 reviews
Search Allegiant Air flights
JetBluePriceFrom $126Free CancellationRating
7.1
3,024 reviews
Search JetBlue flights
American AirlinesPriceFrom $168Free CancellationRating
7.1
11,851 reviews
Search American Airlines flights
SouthwestPriceFrom $169Free CancellationRating
8.0
4,233 reviews
Search Southwest flights
United AirlinesPriceFrom $179Free CancellationRating
7.4
10,034 reviews
Search United Airlines flights

Why use momondo?

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

We help find the flight that best suits your needs, momondo compares prices from hundreds of airlines and travel agents and helps you filter them to find the best flight from Denver to Illinois for you.

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

momondo does allow users to show only those flights to Illinois from Denver which offer a flexible booking policy as well as other useful filters and features.

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

Once all potential Denver to Illinois flight options are in front of you, momondo lets you sort and filter flights based on preferences such as airline, price and flight times amongst many other options.

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

If you are not ready to book a flight from Denver 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.

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