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$98+ Cheap flights from Illinois to Idaho

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.
ORD — BOI
Feb 18 — Feb 251
Wed 2/18
Wed 2/25
1 adult, Economy
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Cheap flight deals from Illinois to Idaho

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

Most accurate provider

eDreams
3 stars

Most trusted provider

eDreams
3 stars

Round-trip from

$180
(Kiwi.com)

One-way from

$98
(Kiwi.com)

Popular in

November

Cheapest in

September

Average price

$425

Good round-trip deal

$317 or less

Good one-way deal

$245 or less
Provider with most accurate pricing for Chicago (CHI)-Boise Air Term. Gowen Fld flight deals.
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Provider most trusted by Cheapflights users for Chicago (CHI)-Boise Air Term. Gowen Fld flights.
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From Illinois to Idaho
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One-way flight from Illinois to Idaho
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Highest demand for flights based on searches. 1% potential increase in price ($6 potential increase over avg. RT price).
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Cheapest flight prices on average. 1% potential price decrease ($6 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 Illinois to Idaho.
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Price to beat on a one-way flight from Illinois to Idaho.
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Find flight deals from Illinois to Idaho

Cheapest flights from Illinois to Idaho
Explore the most affordable flight options available from Illinois to Idaho. 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 1/17. 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.
Fri 2/208:20 pm
STL
-
BOI
2 stops39h 51m
Frontier
Fri 2/2711:56 am
BOI
-
STL
1 stop25h 00m
Frontier
Deal found 1/17$180
This Expedia deal was found by Cheapflights users on 1/17. 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.
Mon 2/96:06 pm
ORD
-
BOI
1 stop6h 53m
Multiple Airlines
Thu 2/1212:36 pm
BOI
-
ORD
1 stop9h 38m
Multiple Airlines
Deal found 1/17$210
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.
Wed 2/186:02 pm
ORD
-
GEG
2 stops19h 25m
Frontier
Thu 2/2612:22 pm
GEG
-
ORD
1 stop23h 03m
Frontier
Deal found 1/18$212
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.
Wed 3/45:29 pm
ORD
-
GEG
1 stop8h 30m
Hawaiian Airlines
Wed 3/111:23 pm
GEG
-
ORD
1 stop8h 33m
Hawaiian Airlines
Deal found 1/18$216
This Mytrip deal was found by Cheapflights users on 1/17. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 2/16:41 am
ORD
-
GEG
1 stop13h 31m
Frontier
Thu 2/512:03 pm
GEG
-
ORD
1 stop20h 54m
Frontier
Deal found 1/17$224
This Kiwi.com deal was found by Cheapflights users on 1/17. 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.
Wed 4/13:29 pm
ORD
-
BOI
1 stop20h 39m
Multiple Airlines
Mon 4/65:54 pm
BOI
-
ORD
2 stops28h 56m
Multiple Airlines
Deal found 1/17$226
This Alaska Airlines deal was found by Cheapflights users on 1/17. 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.
Thu 3/53:54 pm
ORD
-
BOI
1 stop7h 46m
Alaska Airlines
Mon 3/91:00 pm
BOI
-
ORD
1 stop9h 56m
Alaska Airlines
Deal found 1/17$229
This Expedia deal was found by Cheapflights users on 1/17. 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.
Wed 5/273:43 pm
ORD
-
GEG
1 stop10h 09m
Alaska Airlines
Wed 6/37:00 am
GEG
-
ORD
1 stop9h 46m
Alaska Airlines
Deal found 1/17$235
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.
Tue 3/316:29 am
STL
-
BOI
1 stop8h 35m
Delta
Tue 3/316:15 pm
BOI
-
STL
1 stop5h 06m
Delta
Deal found 1/18$237
This Kiwi.com deal was found by Cheapflights users on 1/17. 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.
Wed 4/13:29 pm
ORD
-
BOI
1 stop20h 39m
Frontier
Sun 4/512:03 pm
BOI
-
ORD
1 stop24h 16m
Frontier
Deal found 1/17$238
This United 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 3/3111:15 am
STL
-
BOI
2 stops11h 07m
United Airlines
Sat 4/42:37 pm
BOI
-
STL
1 stop5h 17m
United Airlines
Deal found 1/18$242
This Southwest deal was found by Cheapflights users on 1/17. 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.
Wed 2/1810:05 am
MDW
-
BOI
1 stop6h 15m
Southwest
Sat 2/2112:40 pm
BOI
-
MDW
1 stop10h 05m
Southwest
Deal found 1/17$247

Cheapflights Fare Finder

 
Customize your flight search to find flights from Illinois to Idaho 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 Illinois to Idaho that are best for you.

Fly from

Illinois

Fly to

Idaho

Route

Depart

Return

Price

St. LouisBoise

STL - BOI

STLBOI

Lambert-St Louis

Fri 2/20

8:20 pm-11:11 am

2 stops39h 51m

Boise Air Term. Gowen Fld

Fri 2/27

11:56 am-1:56 pm

1 stop25h 00m

$180

St. LouisBoise

STL - BOI

STLBOI

Lambert-St Louis

Wed 4/1

6:12 pm-10:11 pm

1 stop4h 59m

Boise Air Term. Gowen Fld

Sat 4/4

1:55 pm-11:58 pm

1 stop9h 03m

$237

St. LouisBoise

STL - BOI

STLBOI

Lambert-St Louis

Sat 2/28

4:30 pm-9:32 pm

1 stop6h 02m

Boise Air Term. Gowen Fld

Wed 3/4

2:40 pm-8:26 pm

1 stop4h 46m

$237

St. LouisBoise

STL - BOI

STLBOI

Lambert-St Louis

Tue 3/31

6:29 am-2:04 pm

1 stop8h 35m

Boise Air Term. Gowen Fld

Tue 3/31

6:15 pm-12:21 am

1 stop5h 06m

$237

St. LouisBoise

STL - BOI

STLBOI

Lambert-St Louis

Tue 3/31

4:30 pm-10:35 pm

1 stop7h 05m

Boise Air Term. Gowen Fld

Wed 4/1

2:37 pm-8:54 pm

1 stop5h 17m

$237

St. LouisBoise

STL - BOI

STLBOI

Lambert-St Louis

Wed 4/1

11:15 am-9:22 pm

2 stops11h 07m

Boise Air Term. Gowen Fld

Sat 4/4

2:37 pm-8:54 pm

1 stop5h 17m

$242

ChicagoBoise

MDW - BOI

MDWBOI

Chicago Midway

Wed 2/18

10:05 am-3:20 pm

1 stop6h 15m

Boise Air Term. Gowen Fld

Sat 2/21

12:40 pm-11:45 pm

1 stop10h 05m

$247

ChicagoBoise

ORD - BOI

ORDBOI

Chicago O'Hare Intl

Sat 5/2

6:00 am-12:35 pm

1 stop7h 35m

Boise Air Term. Gowen Fld

Tue 5/5

7:30 am-7:03 pm

1 stop10h 33m

$249

ChicagoSpokane

ORD - GEG

ORDGEG

Chicago O'Hare Intl

Tue 6/2

6:00 am-12:52 pm

1 stop8h 52m

Spokane

Sat 6/6

7:00 am-6:46 pm

1 stop9h 46m

$255

St. LouisJackson

STL - JAC

STLJAC

Lambert-St Louis

Thu 4/30

2:22 pm-7:01 pm

1 stop5h 39m

Jackson Hole

Sun 5/3

5:00 pm-12:22 am

1 stop6h 22m

$257

Flights are sorted by cheapest round-trip flights first.

Deals found on 1/19

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

Have a flexible travel schedule? Discover the best time to fly to Idaho from Illinois 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 Illinois to Idaho

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

Currently, July is the cheapest month in which you can book a flight from Illinois to Idaho (average of $149). Flying from Illinois to Idaho in December is currently the most expensive (average of $288). 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 IL to ID?

Find hourly flight availability from Illinois to Idaho. 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 typically best to fly out from Illinois to Idaho at noon. Doing so could potentially save you 32% on the flight price compared to flying in the afternoon, which is usually more expensive.

Weekly flight availability from Illinois to Idaho

Explore weekly flight availability from Illinois to Idaho. 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 USIL to USID are scheduled on a Monday (6 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (5 on average).

Reviews of airlines servicing Idaho

Get insights into the airlines that provide service to Idaho. 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 Idaho. Reviews last updated January 19, 2026.
Read reviews from past customers who have flown Alaska Airlines, Southwest, and Delta from Illinois to Idaho. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
11,745 reviews

Crew

8.5

Boarding

8.1

Entertainment

7.0

Comfort

7.8

Food

7.1

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

Crew

8.5

Boarding

8.1

Entertainment

7.0

Comfort

7.8

Food

7.1

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

Crew

8.5

Boarding

8.1

Entertainment

7.0

Comfort

7.8

Food

7.1

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

Crew

8.5

Boarding

8.1

Entertainment

7.0

Comfort

7.8

Food

7.1

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

Crew

8.5

Boarding

8.1

Entertainment

7.0

Comfort

7.8

Food

7.1

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

Crew

8.5

Boarding

8.1

Entertainment

7.0

Comfort

7.8

Food

7.1

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 Illinois to Idaho. 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 Illinois to Idaho?

    There are many flights that can get you from Illinois to Idaho in 4h 59m. Fly via Frontier, Delta, or United Airlines to get the fastest option. Illinois and Idaho are separated by a distance of 1378 mi. Both multi-stop and nonstop flights can be found to your destination and back.

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

    One-way options have recently been found by users for as low as $77 on Alaska Airlines. Other airlines that offer cheap prices include Delta from $87 and Southwest from $87 one-way.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from Illinois to Idaho 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 Illinois to Idaho?

    Currently, July is the cheapest month in which you can book a flight from Illinois to Idaho (average of $149). Flying from Illinois to Idaho in December is currently the most expensive (average of $288). 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 Illinois to Idaho

See prices for flight routes from nearby airports that may be better suited for you.
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Top 4 airlines flying from Illinois to Idaho

Discover the top 4 airlines that operate flights from Illinois to Idaho. 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$174Average$325FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$237Average$439FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$248Average$459FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$254Average$333FlexibilityNo cancel feeOn-time63%

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