$30 Find Cheap Flights from Denver to Illinois

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Denver to Illinois departing on 11/1. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy

KAYAK searches hundreds of travel sites at once for deals on flights to Illinois

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Denver to Illinois, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Denver to Illinois, as well as popular online travel agencies
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Cheap Flights from Denver to Illinois

Cheapest round-trip prices found by our users on KAYAK in the last 72 hours
Chicago
Chicagononstop$49
Moline
Moline1 stop$229
Peoria
Peorianonstop$113
Bloomington
Bloomington1 stop$339
Champaign
Champaign1 stop$465
Springfield
Springfield1 stop$367
Decatur
Decatur1 stop$344
St. Louis
St. Louisnonstop$54
Chicago
Chicagononstop$49
Moline
Moline1 stop$229
Peoria
Peorianonstop$113
Bloomington
Bloomington1 stop$339
Champaign
Champaign1 stop$465
Springfield
Springfield1 stop$367
Decatur
Decatur1 stop$344
St. Louis
St. Louisnonstop$54

Book Cheap Denver to Illinois Plane Tickets

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Denver to Illinois that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Denver to Illinois

Tue, Oct 7 - Thu, Oct 9
Frontier Logo
8:22 pm - 11:53 pmDEN-ORD
2h 31mnonstop
Frontier Logo
6:00 am - 7:41 amORD-DEN
2h 41mnonstop
$49Frontier
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Sat, Oct 4 - Tue, Oct 7
Frontier Logo
6:00 am - 9:06 amDEN-STL
2h 06mnonstop
Frontier Logo
7:52 pm - 9:20 pmSTL-DEN
2h 28mnonstop
$54Frontier
Find Deal
Fri, Nov 14 - Mon, Nov 17
Allegiant Air Logo
5:50 pm - 8:47 pmDEN-PIA
1h 57mnonstop
Allegiant Air Logo
12:09 pm - 1:34 pmPIA-DEN
2h 25mnonstop
$113Allegiant Air
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Fri, Oct 3 - Mon, Oct 6
Allegiant Air Logo
6:41 pm - 9:32 pmDEN-PIA
1h 51mnonstop
Allegiant Air Logo
11:59 am - 1:15 pmPIA-DEN
2h 16mnonstop
$115Allegiant Air
Find Deal
Sat, Sep 13 - Tue, Sep 16
Southwest Logo
8:00 am - 11:25 amDEN-MDW
2h 25mnonstop
Southwest Logo
8:20 am - 9:55 amMDW-DEN
2h 35mnonstop
$157Southwest
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Wed, Sep 3 - Mon, Sep 8
Southwest Logo
1:10 pm - 4:30 pmDEN-MDW
2h 20mnonstop
Southwest Logo
11:10 am - 12:40 pmMDW-DEN
2h 30mnonstop
$169Southwest
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Sat, Aug 23 - Mon, Aug 25
United Airlines Logo
2:45 pm - 8:52 pmDEN-PIA
5h 07m1 stop
United Airlines Logo
8:45 am - 10:26 amPIA-DEN
2h 41mnonstop
$219United Airlines
Find Deal
Fri, Aug 22 - Sun, Aug 24
American Airlines Logo
3:35 pm - 11:01 pmDEN-MLI
6h 26m1 stop
American Airlines Logo
10:42 am - 5:46 pmMLI-DEN
8h 04m1 stop
$229American Airlines
Find Deal
Thu, Aug 14 - Tue, Aug 19
American Airlines Logo
3:54 pm - 11:59 pmDEN-PIA
7h 05m1 stop
American Airlines Logo
4:15 pm - 10:55 pmPIA-DEN
7h 40m1 stop
$239American Airlines
Find Deal
Tue, Oct 21 - Wed, Oct 29
United Airlines Logo
5:52 pm - 9:05 pmDEN-PIA
2h 13mnonstop
United Airlines Logo
8:43 am - 10:35 amPIA-DEN
2h 52mnonstop
$279United Airlines
Find Deal
Booking Insights

KAYAK's insights & trends for Denver to Illinois flights

Get data-powered insights and trends into flights from Denver to Illinois to help you find the cheapest flights, the best time to fly and much more.

What is the cheapest Denver to Illinois flight route?

The cheapest price for flight routes found by users searching on KAYAK in the last 2 weeks for round-trip flights from Denver to Illinois.

The cheapest ticket to Illinois from Denver found in the last 72 hours was to Peoria, at $89 round-trip. The most popular route is from Denver (DEN) to Chicago O'Hare Intl Airport (ORD), and the cheapest round-trip airline ticket found on this route in the last 72 hours was $123.

Can I save money by flying with a layover from Denver to Illinois?

The average round-trip price for all non-stop flights, flights with one layover, and flights with two layovers for the route found by users searching on KAYAK in the last 2 weeks.

No, with an average price for the route of $440, prices are generally cheapest when you fly direct.

What is the cheapest month to fly from Denver to Illinois?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Denver to Illinois, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.

The cheapest month for flights from Denver to Illinois is September, when tickets cost $157 (return) on average. On the other hand, the most expensive months are May and July, when the average cost of round-trip tickets is $229 and $221 respectively.

What’s the cheapest day of the week to fly from Denver to Illinois?

The average price of all round-trip flights from Denver to Illinois clicked on KAYAK for each day over the last 12 months.

If you are looking for a flight deal from Denver to Illinois, look for departures on Fridays and avoid leaving on a Sunday, as it's usually the priciest day. When flying back from Illinois, Saturday is the cheapest day to fly and Sunday is the most expensive.

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

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from Denver to Illinois, removes the top 0.1% to account for outliers, and then takes the average of all the values for each week.

To get a below average price on the flight from Denver to Illinois, you should book around 3 weeks before departure, which saves you about 30% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 5 weeks before departure.


Good to know

Low seasonFebruary
Cheapest flight$30
Best time to beat the crowds with an average 4% drop in price.
Most popular time to fly and prices are also 18% lower on average.
Flight from Denver to St. Louis

Flights from Denver to Illinois: the best tips from KAYAK users

Insights shared by verified travelers who flew the route from Denver to Illinois 
AdamFlew with SouthwestDEN-ORDOct 2024
Arriving T5 at ORD on Southwest is often a LONG walk, with no moving walkways going out, to baggage claim / pickup.
BrianFlew with United AirlinesDEN-ORDJan 2024
Big airport. Make sure you have enough time between flights for rest, eating, etc…

FAQs - booking Illinois flights

  • How does KAYAK find such low prices on flights from Denver to Illinois?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Denver to Illinois.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Denver to Illinois?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight from Denver to Illinois is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Denver to Illinois?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly from Denver to Illinois with an airline and back with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Denver to Illinois?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying from Denver to Illinois up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

  • What is the cheapest time of day to fly to Illinois?

    The cheapest time of day to fly to Illinois is generally at night, when round-trip flights cost $189 on average. Morning departures are around 5% cheaper than evening flights, on average. The most expensive time of day to fly to Illinois is generally in the afternoon, which is peak travel time and where the average cost of a ticket is $638.

Top tips for finding cheap flights to Illinois

  • Looking for a cheap flight? 25% of our users found tickets from Denver to the following destinations at these prices or less: Chicago $126 one-way - $210 round-trip

Reviews of the top 5 airlines serving from Denver to Illinois

 
See real verified KAYAK customer reviews for airlines flying from Denver to Illinois. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from Denver to Illinois? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
8.0
SouthwestOverall score based on 4241 reviews
8.0Comfort
8.1Boarding
7.0Food
8.6Crew
7.5Entertainment
Airline reviews

WiFi did not work. For as outrageous as these flights cost, when they’re advertised with certain services/ features they should be in working order

2.0 MediocreMike, Jul 2025DEN - BWI
Read more Southwest reviews

WiFi did not work. For as outrageous as these flights cost, when they’re advertised with certain services/ features they should be in working order

Worst experience I had on Southwest. Still better than most, but the seating was barely tolerable.

It was okay. The plane was delayed from earlier in the day, but they kept updating the departure time, sometimes later, sometimes earlier. That was stressful. Once we finally got on and took off, it was fine. I was supposed to have a connection in Chicago to Los Angeles, and the time for so late I was rebooked to arrive in LA 3 hours late. The departure time to Chicago later became early enough to have taken my original connection and arrive earlier but that wasn't an option.

Everything was on time. I was disappointed by the front section female, African American flight attendant. I did not see her name tag or would have identified by name not race. As passengers moved to the bathroom early in flight, she would say with a disdainful tone “I have to say the seat belt light is on” then go back to her book. Better trained flight attendants say something like be careful the seat belt light is on.

I would have liked to arrive on time - not 5 hours late!

1.5 hour delay, poor service, no compassion from the crew. Terrible experience

Our flight was diverted from being a non-stop to getting within 150 miles and requiring another plane. We heard 4 or 5 different versions from SW as to why we had to stop, then wait for a replacement plane. Five hour delay, weather did not come up as a single excuse.... communication was not clear and well explained. No one really took charge!

Flight was awfully bumpy and landing was a bit jolting. I was in the restroom when snacks and drinks were served and was not asked if i wanted any. I had to ask for water finally.

I really like open seating. I hate that I've heard this is going away. This is one of the unique things that makes Southwest my goto choice.

It seems as though the provisions are even less. Although SWA used to be an economy Airline, that isn't really the case anymore. I paid over $700. for a round trip to Denver and I could have flown just about any airline for the price. The drinks are now in a 6-ounce cup and with ice I'm sure a can would fill more than 2 cups. However, I am very proud of SWA for using paper rather than continuing to contribute to the millions of plastic cups being used each day. I've thought of this fr many years and am so glad to see it come to fruition, if not by only SWA so far.

Impressed with the service despite turbulence because of the weather. Both flights arrived before their scheduled times.

Great experience…left a bit behind schedule but made up fir that in the air and landed 10 minutes early 😁

Electric plugs didn't work. Entertainment system wasn't working

The design of the light switch on the arm rest is ridiculous.

The gate attendant let me walk right by her with a bag too big for the overhead compartment

Overall, it was a good experience. Boarding was good and there was plenty of overhead bin space for everyone’s carryons (even when we boarded toward the end). Only improvement would be to offer trash service more regularly.

David went above and beyond to make our flight the best that it could be

No food service almost missed because of first flight delays

Had a hard time finding my assigned seat. No attendants to assist.

The negative was the wait at the airport coming back. I checked my bags in, an hour before boarding and I get the notification that my flight was delayed. Rather had gotten the notification while I was at the hotel. Then it was delayed 3 x’s. Ugh!

Couldn’t get the door on the plane to close leading to a nearly 2 hour delay. But, hey at least they didn’t cancel the flight.

The flight was fine and the crew awesome. The problem is ORD and AA. Computers went down, ORD fell apart and a 40 min flight turned into a 3 hour trip. Guess the answer is to not try and fly to ORD after noon. But, as I said, crew was awesome and did everything they could to lesson the flight time.

The flight was fine but the 8 hour delay in Chicago was awful - 5 gate changes and repeated delays without an explanation. No vouchers. Nothing.

Mechanical delay and no compensation. Missed connection as a result of their delay. Mediocre performance and service. Horrible airline currently with horrible culture.

Most miserable flight ever. We waited almost 2 hours on the runway because the flight was oversold. American offered $1200 credit. Then there was some nonsense about weight distribution. Ridiculous. No food for 8 plus hours on the flight. I will be writing a letter.

The flight was 2 hour delayed, otherwise everything was excellent. The delay was due to the hourly limit requirement so given that as a reason, I'm happy with the flight!

Not sure the logic of the boarding in Groups. I was loaded first on the aisle. Then the guy in the middle. Then the guy by the window. Constantly holding up the other people boarding behind them with us blocking the aisle and this happened in most of the other rows

Any sort of gluten free snack option would be nice

To start, I’d like to say that every American Airline personnel I interacted with on the ground, especially flight crew, was very friendly and did their best to help me out. Despite this, however, my experience with the airline was an entire mess. The 7:19 PM flight was heavily delayed due to weather, and pushed to 10:30 AM the next morning. Because of this, I had to spend the night inside of the airport. At some point later in the night, I got an email saying that the flight had been canceled. I called the support number, and the representative on the other line told me that the flight was still on and that I didn’t need to rebook. The next morning, no one came to the gate to open the door for the crew until almost 11 AM. By this time the flight crew had been waiting for over an hour, and they had called management to get someone to open the door for them multiple times. Around 11:30, the gate screen had changed to a different flight. I ended up buying a last minute ticket with Southwest airline just to get to Chicago, because the next flight with American wasn’t until 7:19 pm that day. Now, earlier that morning my suitcase had been sent ahead of me to ORD. I went to baggage claim to ask them if I could have my suitcase forwarded to where I was staying. The representative at SDF baggage claim said they could and put the claim in for me. As I was going back through TSA, I got an email that the airline had found my suitcase, but the next step was to send it BACK to SDF. I called the airline support number again, and I made it clear that my suitcase needed to stay in Chicago and to not come back to SDF. The representative told me that they would hold my suitcase at ORD and that it wasn’t going to be forwarded anywhere. Once I got there, I found that they had loaded my suitcase onto a plane to send it back to SDF. Thankfully, I had gotten to the baggage claim counter in time for them to put in a request to bring my suitcase back up. My refund with the airline is processing already, but because of this entire experience and miscommunication at every turn of the way, I will not book with American Airlines in the future.

The plane was late and then sat on the runway for almost 45 minutes before taking off.

It was canceled. The flight wasn’t rescheduled, everyone had to figure out their own new arrangements. They said we would get refunded our original fare and receive an additional $150. We received links for $100 only and they expired before we could activate them.

The plane had originated in Las Vegas at 6:30 in the morning and flew to Moline where we boarded. The flight left around 12:30 PM and there were no boxed snacks available and many of the alcoholic beverages were unavailable. I would find it hard to believe that that many of the passengers coming from Las Vegas at 6:30 in the morning, drank and ate that much of the items. I can only come to the conclusion that someone failed to stock the plane for the round-trip. This is a huge revenue failure for the airline and disappointment for the passengers. The flight crew did not seem happy to be there and did not engage with passengers. Allegiant you can do better.

They did not let my husband on the plane with our service animal at the last minute. Do NOT fly this airline with a service animal!

Tight! Seats are not designed for those of us who wear extra-large clothes.

The non-stop flight from Grand Rapids was excellent. I neither expected or needed a budget flight and Allegiant made the trip easy and for an affordable price, Arriving at the Mesa Airport (AZA) is a delight compared to the international airport. For our return flight, we were able to arrive 75 minutes before the flight, return the rental car, check our bag and make it to the gate in plenty of time. That would never happen at most airports.

Easiest flights I’ve ever taken. Plane was comfortable without overly crowded seating.

Terrible. Still have not received the refund from them. They sent it to some account that I don't even know. Spoke with costumer service and they are unable to help.

I didn’t like it at all. I miss my second flight because of the delay on Allegiant Air now I m stuck in MCO.

Good, but a bit late on take off after loading. Don't like charging for carry ons!

First time flying with them and will definitely fly again in the future. Crew was so nice and friendly, fought was seamless. They are simple planes, no entertainment, but it’s fine for a short flight or if you have personal devices Rates are competitive, and they did so well with keeping the flight on time after a tropical storm, where other airlines had delays and cancellations.

I’m not gonna fly Frontier Airlines because booking is not an option. No water or food is for high price, not equipped for health emergency incompetent crew for emergency services. Cheap airline shows it is cheaper in all service categories. Boarding is the best of all airlines!

Very bad! No good service delayed my second connection flight

Frontier is terrible. Paid for exit row, not given exit row, refused to refund fee.

2 hour delay due to late plane, wrong size plane causing overbooking, and people getting off and on the plane after boarding was completed.

The worst. We never made our connection and they did absolutely nothing to help us at the airport.

I never got to experience the flight because they delayed my first flight and I missed this one. Then Frontier didn't want to help me rebook a flight to get me to my final destination.

The Boarding process in Denver was chaotic, and since the line was so long, we were lined up very far from the gate. If there were any announcements from the gate staff, we didn't hear them. The flight attendants were spectacular. The only negative part of the flight was sitting by a 2 1/2 year old who was unruly and unfortunately had parents that matched his behaviors. Also, the restaurants in Denver on the E concourse, they didn't have food (passengers could only order 1 item on the entire menu) or the restaurants had 12-14 people waiting for orders to be prepared and another 6 people waiting to order. If you have a layover in Denver and need to grab food, be prepared to visit the shops with pre-packaged sandwiches, or you can visit another concourse but it may take a while to transit throughout the airport.

Everything went as planned. Crew was great. Seats were still not that comfortable.

they delayed my flight which ended up, causing my layover flight to leave without me, resulting in me missing a flight and having to stay overnight in Houston international. I got no compensation other than a flight to my original location only a day later. i’ve never experienced such a unprofessional situation

The seats were extremely hard and uncomfortable, even for a budget airline.

Everything you need to know for your flight from Denver to Illinois

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