$38+ Cheap flights from Colorado to Illinois
This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 2/21. Fares are subject to change and may not be available on all flights or dates of travel.
Find cheap flights from Colorado to Illinois with Cheapflights
1. Tell us where you want to go
Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”2. Select your favorite providers
We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.3. Compare prices and book
Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.Cheap flight deals from Colorado to Illinois
Discover tips and strategies to find the most affordable flight options for your journey from Colorado (USCO) to Illinois (USIL). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated January 21, 2025.
Round-trip from | $58 (Frontier) |
|---|---|
One-way from | $38 (Cheapflightsfares) |
Good round-trip deal | $122 or less |
Good one-way deal | $79 or less |
Find flight deals from Colorado to Illinois
Cheapest flights from Colorado to IllinoisExplore the most affordable flight options available from Colorado to Illinois. Find the lowest fares from popular airlines and budget airlines, with prices last updated on January 21, 2025.
Explore the most affordable flight options available from Colorado to Illinois. Find the lowest fares from popular airlines and budget airlines, with prices last updated on January 21, 2025.
This Kiwi.com deal was found by Cheapflights users on 1/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This Frontier deal was found by Cheapflights users on 1/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This Frontier deal was found by Cheapflights users on 1/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This Southwest deal was found by Cheapflights users on 1/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This Southwest deal was found by Cheapflights users on 1/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This Kiwi.com deal was found by Cheapflights users on 1/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This American Airlines deal was found by Cheapflights users on 1/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This United Airlines deal was found by Cheapflights users on 1/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This Delta deal was found by Cheapflights users on 1/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This Delta deal was found by Cheapflights users on 1/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This American Airlines deal was found by Cheapflights users on 1/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This Southwest deal was found by Cheapflights users on 1/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Find flights from Colorado to Illinois within your budget
Customize your flight search to find flights from Colorado 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, Cheapflights users made 2,558,603 searches. Data last updated January 21, 2025.
Fly from
Fly to
Route
Depart
Return
Price
DenverSt. Louis
DEN - STL
DENSTL
Denver Intl
Wed 2/5
6:00 am-9:16 am
Nonstop2h 16m
Lambert-St Louis
Sat 2/8
7:09 pm-8:37 pm
Nonstop2h 28m
DenverChicago
DEN - ORD
DENORD
Denver Intl
Thu 2/13
9:53 am-1:25 pm
Nonstop2h 32m
Chicago O'Hare Intl
Mon 2/17
6:50 am-8:53 am
Nonstop3h 03m
DenverChicago
DEN - MDW
DENMDW
Denver Intl
Sat 2/15
8:55 pm-12:17 am
Nonstop2h 22m
Chicago Midway
Thu 2/27
6:40 am-8:32 am
Nonstop2h 52m
DenverChicago
DEN - ORD
DENORD
Denver Intl
Thu 4/10
7:30 pm-11:05 pm
Nonstop2h 35m
Chicago O'Hare Intl
Wed 4/16
7:00 am-8:40 am
Nonstop2h 40m
DenverChicago
DEN - MDW
DENMDW
Denver Intl
Sat 3/1
5:40 am-9:05 am
Nonstop2h 25m
Chicago Midway
Sun 3/2
10:25 pm-12:15 am
Nonstop2h 50m
DenverChicago
DEN - ORD
DENORD
Denver Intl
Thu 7/10
10:20 am-7:11 pm
1 stop7h 51m
Chicago O'Hare Intl
Thu 7/31
5:35 am-7:27 am
Nonstop2h 52m
DenverSt. Louis
DEN - STL
DENSTL
Denver Intl
Wed 3/5
6:30 am-2:52 pm
1 stop7h 22m
Lambert-St Louis
Wed 3/5
4:20 pm-11:20 pm
1 stop8h 00m
DenverChicago
DEN - ORD
DENORD
Denver Intl
Wed 4/9
6:02 am-9:34 am
Nonstop2h 32m
Chicago O'Hare Intl
Wed 4/16
9:15 pm-11:10 pm
Nonstop2h 55m
DenverChicago
DEN - ORD
DENORD
Denver Intl
Thu 2/13
6:15 am-12:55 pm
1 stop5h 40m
Chicago O'Hare Intl
Tue 2/18
10:10 am-5:03 pm
1 stop7h 53m
DenverChicago
DEN - MDW
DENMDW
Denver Intl
Fri 2/21
6:15 am-1:05 pm
1 stop5h 50m
Chicago Midway
Mon 2/24
6:59 pm-10:46 pm
1 stop4h 47m
Best time to book a flight from Colorado to Illinois
Have a flexible travel schedule? Discover the best time to fly to Illinois from Colorado with our price prediction graph.
Travel insights for flights from Colorado to Illinois
Get recent, data-driven insights about flights from Colorado to Illinois including ideal travel times, pricing trends, and more.
What is the cheapest month to book a flight from Colorado to Illinois?
Currently, August is the cheapest month in which you can book a flight from Colorado to Illinois (average of $245). Flying from Colorado to Illinois in March is currently the most expensive (average of $320). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.
What is the cheapest time of day to fly from CO to IL?
Find hourly flight availability from Colorado to Illinois. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated January 21, 2025.
Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Colorado to Illinois as you normally would.
Weekly flight availability from Colorado to Illinois
Explore weekly flight availability from Colorado to Illinois. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated January 21, 2025.
The most flights from USCO to USIL are scheduled on a Monday (48 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (18 on average).
Rainfall in Illinois by month
Plan your trip to Illinois by taking into account the average rainfall totals by month.
In terms of precipitation, rainfall in Illinois ranges from 1.7 - 4.9 inches per month. August is typically the wettest month, when rainfall can reach 4.9 in. January is typically the driest time to visit Illinois when rainfall is around 1.7 in.
Temperature in Illinois by month
Plan your trip to Illinois by taking into account the average temperature totals by month.
If weather is an important factor for your trip to Illinois, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 73.4 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 23.0 F).
Reviews of airlines servicing Illinois
Get insights into the airlines that provide service to Illinois. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Illinois. Reviews last updated January 21, 2025.
Read through reviews of airlines operating flights from Colorado to Illinois, such as Alaska Airlines, Southwest and United Airlines. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Comfort
Boarding
Crew
Entertainment
Overall
Food
Reviews
We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.
Comfort
Boarding
Crew
Entertainment
Overall
Food
Reviews
We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.
Comfort
Boarding
Crew
Entertainment
Overall
Food
Reviews
We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.
Comfort
Boarding
Crew
Entertainment
Overall
Food
Reviews
We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.
Comfort
Boarding
Crew
Entertainment
Overall
Food
Reviews
We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.
Comfort
Boarding
Crew
Entertainment
Overall
Food
Reviews
We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.
Related info for your journey
Find useful and relevant information for your journey from Colorado to Illinois. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
Browse thousands of different options on Cheapflights for your next trip
Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.
Alternative routes for Colorado to Illinois
See prices for flight routes from nearby airports that may be better suited for you.
Top 5 airlines flying from Colorado to Illinois
Discover the top 5 airlines that operate flights from Colorado to Illinois. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated January 21, 2025.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$40 | Average$144 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$90 | Average$166 | FlexibilityNo cancel fee | On-time88% | |
| Cheapest$139 | Average$457 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$141 | Average$447 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$154 | Average$313 | FlexibilityNo cancel fee | On-time63% |