$39 Find Cheap Flights from Illinois to Colorado

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Low seasonApril
Cheapest flight$39
Best time to beat the crowds with an average 8% drop in price.
Most popular time to fly and prices are also 3% lower on average.
Flight from Chicago O'Hare Airport to Denver

FAQs for booking flights from Illinois to Colorado

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

    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 Illinois to Colorado.

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

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight from Illinois to Colorado 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 Illinois to Colorado?

    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 Illinois to Colorado 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 Illinois to Colorado?

    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 Illinois to Colorado up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

  • Which airlines fly most frequently to Colorado?

    Illinois and Colorado are connected by different airlines. The airlines that fly that route the most regularly are United Airlines (113 flights per week), Air Canada (74 flights per week), and Southwest (73 flights per week).

  • How many airports are there in Colorado?

    There are 13 airports in Colorado. The busiest airport is Denver Airport (DEN), with 89% of all flights arriving there.

  • Which is the cheapest airport to fly into in Colorado?

    Prices will differ depending on the departure airport, but generally, the cheapest airport to fly to in Colorado is Denver Intl Airport (DEN), with an average flight price of $174.

  • What is the cheapest day to fly to Colorado?

    Based on KAYAK data, the cheapest day to fly to Colorado is Saturday where round-trip tickets can be as cheap as $246. On the other hand, the most expensive day to fly is Sunday, where round-trip prices are $300 on average.

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

    The cheapest time of day to fly to Colorado is generally in the evening, when round-trip flights cost $228 on average. Morning departures are around 11% more expensive than evening flights, on average. The most expensive time of day to fly to Colorado is generally in the afternoon, which is peak travel time and where the average cost of a ticket is $315.

  • What is the cheapest flight to Colorado?

    The cheapest ticket to Colorado from Illinois found in the last 72 hours was to Denver, at $46 round-trip. The most popular route is Bloomington (BMI) to Denver (DEN) and the cheapest round-trip airline ticket found on this route in the last 72 hours was $46.

  • What is the cheapest month to fly from Illinois to Colorado?

    The cheapest month for flights from Illinois to Colorado is November, when tickets cost $163 (return) on average. On the other hand, the most expensive months are August and December, when the average cost of round-trip tickets is $238 and $218 respectively.

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

    To get a below average price on the flight from Illinois to Colorado, you should book around 3 weeks before departure, which saves you about 27% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 5 weeks before departure.

  • How many cities have direct flights to Colorado?

    From Illinois, there are direct flights to Colorado from 3 cities. The city with the most direct flights is Chicago, with 526 direct flights each week.

  • How many direct flights to Colorado are there each day?

    There are around 78 direct flights from within Illinois to Colorado every day. Most flights (36%) depart in the evening.

  • How many direct flights to Colorado are there each week?

    Each week there are around 544 direct flights from within Illinois to Colorado. The most common day for departures is Monday, with 15% of flights taking off on this day.

  • How long is the flight to Colorado?

    An average nonstop flight from Illinois to Colorado takes 7h 56m, covering a distance of 929 miles. The shortest route is St. Louis (STL) to Denver (DEN) with an average flight time of 2h 15m.

  • How many long-haul flights are there to Colorado each week?

    There are not any long-haul (6-12 hour flight duration) or medium-haul (3-6 hour flight duration) flights to Colorado. Instead, there are 544 short-haul flights (up to 3 hour flight duration), with the most arriving from Chicago.

  • What are the most popular destinations in Colorado?

    Based on KAYAK flight searches, the most popular destination is Denver (84% of total searches to Colorado). The next most popular destinations are Colorado Springs (6%) and Vail (3%). Searches for flights to Aspen (2%), to Grand Junction (2%) and to Montrose (1%) are also popular.

Reviews of the top 5 airlines serving from Illinois to Colorado

 
Need help choosing which airline to fly with from Illinois to Colorado? 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 4244 reviews
7.5Entertainment
8.6Crew
8.0Comfort
8.1Boarding
7.0Food
Airline reviews

The Southwest employees (all two of them) were very nice and cheerful despite the fact the line to self-check a bag (simply drop it off) was hundreds of people long. Thank God I arrived early to the airport because I stood in this line for at least an hour. Once on the flight that had been delayed by an hour, we had no Wi-Fi and thus no entertainment. Finally, I hope the investor strong arm tactics against Southwest pay off in a short-term windfall to your C-Suite because the rest of you are screwed. I have been a faithful Southwest customer for 15 years due to everything you just got rid of. I'm flying to Idaho and Washington in October, both places I used to simply book with Southwest without a second thought now with Frontier (Washington) and United (Idaho) because they offer everything the "new" Southwest does but cheaper and at better times, destinations, etc. This really makes me sad...

4.0 OkayGreg, Jul 2025PDX - DEN
Read more Southwest reviews

The Southwest employees (all two of them) were very nice and cheerful despite the fact the line to self-check a bag (simply drop it off) was hundreds of people long. Thank God I arrived early to the airport because I stood in this line for at least an hour. Once on the flight that had been delayed by an hour, we had no Wi-Fi and thus no entertainment. Finally, I hope the investor strong arm tactics against Southwest pay off in a short-term windfall to your C-Suite because the rest of you are screwed. I have been a faithful Southwest customer for 15 years due to everything you just got rid of. I'm flying to Idaho and Washington in October, both places I used to simply book with Southwest without a second thought now with Frontier (Washington) and United (Idaho) because they offer everything the "new" Southwest does but cheaper and at better times, destinations, etc. This really makes me sad...

after landing, we stay 2 hours on the taxi way before reaching the gate The airline and the crew were good though

Flights delayed by 4-6 hours. Boarding was a mess and unclear. Bags were not at arrival airport and had never even been put on the plane. No idea when I’ll get them. Don’t fly into Denver!

Southwest is typically delayed, and it gets wearisome. It is no longer a discount airline and you get way less than you pay for when it comes to comfort and Ce.

We sat on the plane on the tarmac for 4 hours.

I'm not a fan of Southwest's model. I don't like the herding style of boarding.

After a 3 hour layover in Denver my flight was delayed over 5 hours! No explanation; no assistance; no offer to provide compensation; no one at Southwest was willing to offer any assistance. 8 hours in the Denver airport - ridiculous!

My flight to Chicago left and landed early. My return flight left two minutes late and arrived 2 minutes late. My seat selections were ideal! There were no snacks going to Chicago and no snacks on the return trip. There are no charging outlets on board.

WiFi on the flight was not working. Thus, entertainment options were limited.

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.

Excellent flight. Boarding was efficient and departure was on time. Smooth flight with on time arrival. Deplaning was also efficient.

Our flight was understandably diverted to a small regional airport in Laramie, Wyoming due to weather conditions, which I fully recognize and appreciate. However, the low rating stems from the experience that followed: passengers remained on board for over an hour without the option to deplane and stretch, despite the aircraft being stationary. Although the pilot opened the cabin door, only he was permitted to exit. Meanwhile, passengers grew increasingly uncomfortable as warm summer air entered the cabin through the open door, and being in the second row meant we were impacted immediately. While the flight attendants made efforts to keep everyone at ease, I believe allowing passengers to deplane briefly, given the extended delay, would have significantly improved the overall experience.

I never flew. Flight was canceled. DIA worst airport in the country. Avoid at all costs.

Very rough getting into denver. my kid threw up it was so rough.

Why wasn't this flight departure scheduled eith another crew so that it could leave on time? When we arrived in Denver we had so little time between flights we had run to the connecting flight. We should received some credit for the inconvenience.

I was supposed to be on business class at first class from Denver back to Miami due to weather changes. I missed my connection and it’s put on a flight to Fort Lauderdale. Instead of honoring my business class/1st class ticket, they put me in coach, but there were two first class seats open. I think it’s absolutely disgusting that I paid for first class $1300 ticket and they put me in economy and they had to open seats available and I have still not been refunded the difference. I ended up having to eat a snack box instead of the meal I was supposed to get and did not get home till 2 AM so I think that’s a little pathetic that I had to live off crackers for dinner And my poor dog ate some cheese and salami. Oh yes, apparently when they switched me to the new flight they forgot to mention I had a service dog

Excellent service despite turbulence during the flight. Flight attendants were remarkable!

Flight attendant moved my bag without notifying me and was rude to me when I asked him about it. There was no reason to move it.

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

Food choices were very limited. Taste of the dishes was average.

3 hour weather delay followed by 1 hour (and counting) maintenance delay. UGH!

After we'd boarded , they canceled the flight. The crew didn't even know , we just all received text messages. Then after they deplaned us , AA was just like "too bad, go F your self, we sure ain't gonna help you"

After a two hour delay, my flight was CANCELLED! No pilot available. Such BS.

Amazing food, great staff, with one noticable detail missing ...but no seat entertainment in any of aircraft ...I am not a fan

I wish American Airlines would change the airline industry by loading the plane back to front instead of front to back. Planes would board so much more smoothly and quickly.

Terrible. The flight was delayed two hours due to weather. Then when we got on the plane, the first pilot ended up timing out and we had to wait for a second pilot. Second pile came on board and we tax it out. Had to return back to the gate because of an unruly passenger. Then the copilot timed out. Had to wait for new copilot. Also had to wait for maintenance to check for fuel. Then found out the second pilot timed out and we had to wait for a third pilot. Was ready to go and then needed maintenance again for another issue. In the end, it was 2 o’clock in the morning when they announced that the flight couldn’t go because the third pilot and the second copilot had timed out.

I have long legs, my foot was out in the aisle and when a flight attendant came walking by and I didn't notice, instead of saying "excuse me" or anything like that, she kicked my foot. Extremely rude

Excellent! The gate agents were kind enough to rebook me on an earlier flight saving me from a 6 hour layover. Even my luggage made it despite the fact that the connection was technically too narrow. The flight itself was very comfortable, roomy, and clean. Plenty of space for my carryon items with plugs to charge my phone. After a long international flight of 14 hours, this was an excellent way to end my travels!

One of the best flights I’ve had. So smooth.

Great experience. Flight boarded easily. Departed early. Smooth flight. Great arrival in DC--almost no taxing! Almost direct to gate from runway. Crew was terrific. Same cookies and beverages in main cabin. I did not use the entertainment system on this flight.

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.

As every law enforcement agency I could imagine surrounded the plane and we didn’t disembark for 2 hours and then had to stick around for another hour to go get our personal belongings after leaving them behind and being bused away from the plane, it was scary and inconvenient. We were given no information as to why this was happening. Lack of communication with passengers was disappointing.

Frontier Airlines was AWFUL. I was an hour early for my flight and the lady refused to check me in. I had to purchase a whole new ticket with a different airline.

Late, terrible communication, horrible planning of passenger seating until the literal last minute. One of the worst flying experiences of my life. Y'all suck

First of all, we never got on the connecting flight to Denver. They delayed our flight for two hours. If we would have gotten on that flight, we would have been stuck in Denver for 13 hours. So we re- routed our flight for a straight through flight to Oklahoma two days later. THEN, they delayed that flight for two hours. After that we were able to finally get on our flight and come home. Frontier Airlines - one of the worst airlines I have ever been on.

Terrible communication with weather delay, lost baggage, near impossible to reach customer service

My tickets got canceled on me by your site and I didn't have a flight. Then you kept sending me emails on the status of q flight I didn't have tickets for.

Flight was late. Missed connecting in Denver. My new flight is more than 24 hours later and I have no room, vouchers, or compensation, and might also be bumped from the one tomorrow.

This was one of the first frontier airline flights this spring that wasn't delayed. It actually left on time. Some of the flight crew did not look happy, they didn't smile when the passengers were boarding or getting off the plane, and the passengers initiated greetings, not the staff. To me this was an odd experience to have with any flight/airline. I had a bad experience booking this flight. The price didn't solidify until late hours into the night. Ever time I purchased the ticket, I either received a denial email or an error because the price has changed, but it was never reflected on the flyfrontier or kayak websites until way after midnight on the date of travel. This caused me anxiety and irritation with the websites. Then I noticed a mishap with my name on my voucher as I went to check in, it was incorrect. When I proceeded to correct it, Frontier had no easy, let alone free, way to remedy it. I couldn't correct my name without a $75 charge, I couldn't cancel my voucher to repurchase it with the correct name without a $100 charge, because it was too close to departure. Then calling frontier was nearly impossible to remedy the situation with a human. It's already difficult to want to choose frontier because of all the upcharges, but you feel kinda trapped into doing so because it's the more affordable airline.

Our flight was cancelled. They could do nothing to help us get another flight that was timely. Because the first leg was cancelled we were unable to get to our connection. We had to book on an entirely different airline for today. So we spent more money, lost a day of vacation and will never fly Frontier again, so the 'we are sorry, here is $100 credit' is a joke since we won't be flying on Frontier.

I liked the turn-style feature at gate 209B at LAX. Very efficient process. The gate staff also made several, clearly directed announcements so I felt very informed.

Everything you need to know for your flight to Colorado

Cabin class types available on flights to Illinois

Cabin classes available on flights to Illinois. Prices are the lowest found on KAYAK over the last 7 days. Price and availability is not guaranteed.

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