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$84+ Cheap flights from Idaho 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 2/19. Fares are subject to change and may not be available on all flights or dates of travel.
BOI — ORD
Feb 18 — Feb 251
Wed 2/18
Wed 2/25
1 adult, Economy
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Cheap flight deals from Idaho to Illinois

Keep the following information in mind while searching for Idaho to Illinois flight deals. Data was last updated January 19, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

Expedia
3 stars

Round-trip from

$184
(Kiwi.com)

One-way from

$84
(Kiwi.com)

Popular in

December

Cheapest in

February

Average price

$358

Good round-trip deal

$374 or less

Good one-way deal

$259 or less
Provider with most accurate pricing for Boise Air Term. Gowen Fld-Chicago (CHI) flight deals.
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Provider most trusted by Cheapflights users for Boise Air Term. Gowen Fld-Chicago (CHI) flights.
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From Idaho to Illinois
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One-way flight from Idaho to Illinois
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Highest demand for flights based on searches. 2% potential increase in price ($11 potential increase over avg. RT price).
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Cheapest flight prices on average. 0% potential price decrease ($3 potential savings vs. average RT price).
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Average for round-trip flights in January 2026
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Price to beat on a round-trip flight from Idaho to Illinois.
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Price to beat on a one-way flight from Idaho to Illinois.
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Find flight deals from Idaho to Illinois

Cheapest flights from Idaho to Illinois
Explore the most affordable flight options available from Idaho to Illinois. Find the lowest fares from popular airlines and budget airlines, with prices last updated on January 19, 2026.

This Kiwi.com deal was found by Cheapflights users on 1/18. 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.
Thu 3/512:22 pm
GEG
-
STL
1 stop19h 27m
Frontier
Sat 3/78:12 pm
STL
-
GEG
1 stop15h 35m
Frontier
Deal found 1/18$184
This Kiwi.com deal was found by Cheapflights users on 1/18. 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.
Thu 2/1912:22 pm
GEG
-
ORD
1 stop8h 52m
Frontier
Wed 2/2511:51 am
ORD
-
GEG
2 stops25h 36m
Frontier
Deal found 1/18$193
This Kiwi.com deal was found by Cheapflights users on 1/18. 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.
Thu 3/512:22 pm
GEG
-
STL
1 stop19h 27m
Frontier
Wed 3/118:12 pm
STL
-
GEG
1 stop16h 35m
Frontier
Deal found 1/18$194
This Kiwi.com deal was found by Cheapflights users on 1/18. 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.
Sun 2/812:03 pm
GEG
-
STL
1 stop22h 47m
Frontier
Sat 2/282:51 pm
STL
-
GEG
1 stop23h 23m
Frontier
Deal found 1/18$218
This Alaska Airlines deal was found by Cheapflights users on 1/18. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 3/106:28 am
BOI
-
ORD
1 stop9h 05m
Alaska Airlines
Tue 3/177:00 am
ORD
-
BOI
1 stop9h 08m
Alaska Airlines
Deal found 1/18$229
This Expedia deal was found by Cheapflights users on 1/16. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 2/1912:36 pm
BOI
-
ORD
1 stop9h 38m
Multiple Airlines
Mon 2/233:54 pm
ORD
-
BOI
1 stop9h 05m
Multiple Airlines
Deal found 1/16$230
This Orbitz deal was found by Cheapflights users on 1/18. 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 Orbitz is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 2/1912:22 pm
GEG
-
ORD
1 stop8h 52m
Multiple Airlines
Tue 2/243:54 pm
ORD
-
GEG
1 stop9h 07m
Multiple Airlines
Deal found 1/18$233
This Travelocity deal was found by Cheapflights users on 1/18. 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 Travelocity is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 5/122:45 pm
GEG
-
ORD
1 stop7h 14m
Alaska Airlines
Tue 5/193:43 pm
ORD
-
GEG
1 stop10h 09m
Alaska Airlines
Deal found 1/18$235
This Southwest deal was found by Cheapflights users on 1/18. 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.
Sat 2/144:00 pm
BOI
-
MDW
1 stop6h 45m
Southwest
Sat 2/218:05 am
MDW
-
BOI
1 stop7h 45m
Southwest
Deal found 1/18$236
This Delta deal was found by Cheapflights users on 1/18. 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.
Wed 2/112:00 pm
GEG
-
STL
1 stop7h 25m
Delta
Tue 3/36:00 am
STL
-
GEG
1 stop7h 35m
Delta
Deal found 1/18$237
This Trip.com deal was found by Cheapflights users on 1/18. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 2/142:20 pm
BOI
-
ORD
1 stop8h 36m
Hawaiian Airlines
Sat 2/213:07 pm
ORD
-
BOI
1 stop9h 23m
Hawaiian Airlines
Deal found 1/18$238
This Kiwi.com deal was found by Cheapflights users on 1/18. 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.
Sun 2/812:03 pm
GEG
-
STL
1 stop22h 47m
Frontier
Wed 2/258:17 pm
STL
-
GEG
2 stops17h 10m
Frontier
Deal found 1/18$240

Cheapflights Fare Finder

 
Customize your flight search to find flights from Idaho 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 19, 2026.
Use the filters below to find and compare flights from Idaho to Illinois that are best for you.

Fly from

Idaho

Fly to

Illinois

Route

Depart

Return

Price

BoiseChicago

BOI - MDW

BOIMDW

Boise Air Term. Gowen Fld

Sat 2/14

4:00 pm-11:45 pm

1 stop6h 45m

Chicago Midway

Sat 2/21

8:05 am-2:50 pm

1 stop7h 45m

$236

SpokaneSt. Louis

GEG - STL

GEGSTL

Spokane

Sat 3/7

2:05 pm-11:23 pm

1 stop7h 18m

Lambert-St Louis

Wed 3/11

6:29 am-1:10 pm

1 stop8h 41m

$237

SpokaneSt. Louis

GEG - STL

GEGSTL

Spokane

Tue 3/3

4:55 pm-12:25 am

1 stop5h 30m

Lambert-St Louis

Tue 3/10

7:15 am-12:45 pm

1 stop7h 30m

$237

SpokaneChicago

GEG - ORD

GEGORD

Spokane

Thu 4/16

7:43 pm-6:39 am

1 stop8h 56m

Chicago O'Hare Intl

Wed 4/22

8:00 am-1:23 pm

1 stop7h 23m

$242

BoiseChicago

BOI - ORD

BOIORD

Boise Air Term. Gowen Fld

Sat 2/7

6:23 am-2:38 pm

1 stop7h 15m

Chicago O'Hare Intl

Tue 2/10

9:00 am-11:42 pm

1 stop15h 42m

$249

BoiseChicago

BOI - ORD

BOIORD

Boise Air Term. Gowen Fld

Fri 4/17

2:22 pm-11:59 pm

1 stop8h 37m

Chicago O'Hare Intl

Tue 4/21

6:00 am-12:22 pm

1 stop7h 22m

$249

BoiseChicago

BOI - ORD

BOIORD

Boise Air Term. Gowen Fld

Mon 4/20

6:04 pm-6:39 am

1 stop11h 35m

Chicago O'Hare Intl

Sat 5/2

6:00 am-12:35 pm

1 stop7h 35m

$249

SpokaneSt. Louis

GEG - STL

GEGSTL

Spokane

Tue 3/3

7:27 am-12:25 am

2 stops14h 58m

Lambert-St Louis

Wed 3/11

5:25 pm-9:17 pm

1 stop5h 52m

$256

SpokaneChicago

GEG - ORD

GEGORD

Spokane

Thu 2/19

7:00 am-12:50 pm

Nonstop3h 50m

Chicago O'Hare Intl

Wed 2/25

4:00 pm-6:16 pm

Nonstop4h 16m

$262

SpokaneChicago

GEG - ORD

GEGORD

Spokane

Thu 2/19

7:00 am-12:50 pm

Nonstop3h 50m

Chicago O'Hare Intl

Tue 2/24

4:00 pm-6:16 pm

Nonstop4h 16m

$262

Flights are sorted by cheapest round-trip flights first.

Deals found on 1/17

Showing 1-10 of 60 results
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Best time to book a flight from Idaho to Illinois

Have a flexible travel schedule? Discover the best time to fly to Illinois from Idaho with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from Idaho to Illinois

What is the cheapest month to book a flight from Idaho to Illinois?

Currently, May is the cheapest month in which you can book a flight from Idaho to Illinois (average of $87). Flying from Idaho to Illinois in December is currently the most expensive (average of $276). 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 ID to IL?

Find hourly flight availability from Idaho 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 19, 2026.

It’s optimal to fly from Idaho to Illinois in the afternoon. By choosing this option you can save up to 44% on the cost of your flight, compared to a flight in the evening.

Weekly flight availability from Idaho to Illinois

Explore weekly flight availability from Idaho 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 19, 2026.

The most flights from USID to USIL are scheduled on a Monday (8 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (7 on average).

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 19, 2026.
Read through reviews of airlines operating flights from Idaho to Illinois, such as Alaska Airlines, Southwest, and Delta. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
11,745 reviews

Food

7.1

Boarding

8.1

Entertainment

7.0

Crew

8.5

Comfort

7.8

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jan 2026

STS - LAX

Enjoyed staff assistance from ticking thru tsa , boarding and in the plane Couldn’t pick a seat except upgrading
Alaska Airlines
8.0
Very good
11,745 reviews
Alaska Airlines
8.0
Very good
11,745 reviews

Food

7.1

Boarding

8.1

Entertainment

7.0

Crew

8.5

Comfort

7.8

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jan 2026

STS - LAX

Enjoyed staff assistance from ticking thru tsa , boarding and in the plane Couldn’t pick a seat except upgrading
Southwest
8.0
Very good
4,262 reviews
Alaska Airlines
8.0
Very good
11,745 reviews

Food

7.1

Boarding

8.1

Entertainment

7.0

Crew

8.5

Comfort

7.8

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jan 2026

STS - LAX

Enjoyed staff assistance from ticking thru tsa , boarding and in the plane Couldn’t pick a seat except upgrading
Delta
7.9
Good
8,075 reviews
Alaska Airlines
8.0
Very good
11,745 reviews

Food

7.1

Boarding

8.1

Entertainment

7.0

Crew

8.5

Comfort

7.8

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jan 2026

STS - LAX

Enjoyed staff assistance from ticking thru tsa , boarding and in the plane Couldn’t pick a seat except upgrading
United Airlines
7.4
Good
9,176 reviews
Alaska Airlines
8.0
Very good
11,745 reviews

Food

7.1

Boarding

8.1

Entertainment

7.0

Crew

8.5

Comfort

7.8

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jan 2026

STS - LAX

Enjoyed staff assistance from ticking thru tsa , boarding and in the plane Couldn’t pick a seat except upgrading
American Airlines
7.2
Good
11,160 reviews
Alaska Airlines
8.0
Very good
11,745 reviews

Food

7.1

Boarding

8.1

Entertainment

7.0

Crew

8.5

Comfort

7.8

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jan 2026

STS - LAX

Enjoyed staff assistance from ticking thru tsa , boarding and in the plane Couldn’t pick a seat except upgrading

Related info for your journey

Find useful and relevant information for your journey from Idaho to Illinois. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • How long is the flight from Idaho to Illinois?

    Departing from Idaho to Illinois will take you 6h 45m. There are 1444 mi between Idaho and Illinois. This flight may include one or multiple stops.

  • What are the cheapest airlines to fly from Idaho to Illinois one-way?

    $87 is the cheapest one-way deal found within the past few days, from Alaska Airlines. You may also be able to find cheap deals on Southwest and Delta, with prices starting from $87 and $87, respectively.

  • Can I find deals for flights from Idaho to Illinois that include hotel bookings?

    Yes. In addition to deals on Idaho to Illinois flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Idaho to Illinois?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Idaho to Illinois.

  • Can I find deals for business class flights from Idaho to Illinois?

    Yes. Cheapflights offers flight deals from Idaho to Illinois by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Idaho to Illinois?

    Currently, May is the cheapest month in which you can book a flight from Idaho to Illinois (average of $87). Flying from Idaho to Illinois in December is currently the most expensive (average of $276). 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.

See more FAQs

Browse thousands of different options on Cheapflights for your next trip

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Alternative routes for Idaho to Illinois

See prices for flight routes from nearby airports that may be better suited for you.
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Top 5 airlines flying from Idaho to Illinois

Discover the top 5 airlines that operate flights from Idaho 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 19, 2026.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$94Average$294FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$221Average$522FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$233Average$388FlexibilityNo cancel feeOn-time63%
American AirlinesCheapest$249Average$447FlexibilityNo cancel feeOn-time71%
Alaska AirlinesCheapest$260Average$358FlexibilityNo cancel feeOn-time75%

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