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$55+ 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 9/6. Fares are subject to change and may not be available on all flights or dates of travel.
BOI — ORD
ago. 12 — ago. 191
mar. 8/12
mar. 8/19
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 agosto 7, 2025.

Round-trip from

$187
(Delta)

One-way from

$55
(FlightHub)

Popular in

December

Cheapest in

January

Average price

$373

Good round-trip deal

$333 or less

Good one-way deal

$171 or less
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. 4% potential increase in price ($17 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($10 potential savings vs. average RT price).
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Average for round-trip flights in August 2025
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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 agosto 7, 2025.

This Delta deal was found by Cheapflights users on 8/5. 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.
mié. 9/35:30 amBOI - STL
1 stop8h 00mDelta
mié. 9/105:30 pmSTL - BOI
1 stop7h 28mDelta
Deal found 8/5$187
This Delta deal was found by Cheapflights users on 8/6. 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.
sáb. 9/276:10 amGEG - STL
1 stop8h 04mDelta
mar. 9/307:40 amSTL - GEG
1 stop6h 15mDelta
Deal found 8/6$187
This Southwest deal was found by Cheapflights users on 8/7. 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.
mar. 10/2112:50 pmGEG - ORD
1 stop8h 50mSouthwest
vie. 10/246:55 pmORD - GEG
1 stop6h 55mSouthwest
Deal found 8/7$194
This American Airlines deal was found by Cheapflights users on 8/6. 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.
mié. 11/56:32 amGEG - ORD
1 stop11h 29mAmerican Airlines
sáb. 11/810:30 amORD - GEG
Nonstop4h 02mAmerican Airlines
Deal found 8/6$195
This Southwest deal was found by Cheapflights users on 8/7. 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.
mié. 9/102:45 pmGEG - MDW
1 stop12h 25mSouthwest
lun. 9/151:25 pmMDW - GEG
Nonstop3h 55mSouthwest
Deal found 8/7$197
This Delta deal was found by Cheapflights users on 8/6. 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.
jue. 10/166:10 amGEG - ORD
1 stop9h 10mDelta
mar. 10/216:00 pmORD - GEG
1 stop7h 59mDelta
Deal found 8/6$201
This American Airlines deal was found by Cheapflights users on 8/7. 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.
mié. 9/241:30 pmGEG - ORD
Nonstop3h 48mAmerican Airlines
lun. 9/2910:46 amORD - GEG
Nonstop3h 58mAmerican Airlines
Deal found 8/7$202
This Delta deal was found by Cheapflights users on 8/7. 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.
vie. 10/2411:15 pmGEG - ORD
1 stop7h 14mDelta
lun. 10/272:20 pmORD - GEG
1 stop8h 45mDelta
Deal found 8/7$203
This Southwest deal was found by Cheapflights users on 8/6. 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.
lun. 9/86:10 amGEG - MDW
1 stop11h 35mSouthwest
dom. 9/1410:30 amMDW - GEG
Nonstop3h 55mSouthwest
Deal found 8/6$206
This Alaska Airlines deal was found by Cheapflights users on 8/5. 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.
jue. 9/42:28 pmBOI - STL
1 stop8h 31mAlaska Airlines
dom. 9/76:00 amSTL - BOI
1 stop10h 00mAlaska Airlines
Deal found 8/5$209
This Delta deal was found by Cheapflights users on 8/6. 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.
vie. 9/197:25 pmGEG - ORD
2 stops11h 03mDelta
dom. 9/218:10 pmORD - GEG
1 stop5h 48mDelta
Deal found 8/6$209
This Delta deal was found by Cheapflights users on 8/7. 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.
vie. 9/1911:35 pmBOI - STL
1 stop8h 09mDelta
lun. 9/225:32 pmSTL - BOI
1 stop7h 27mDelta
Deal found 8/7$210

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 agosto 7, 2025.
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

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

mié. 9/3

5:30 am-2:30 pm

1 stop8h 00m

Lambert-St Louis

mié. 9/10

5:30 pm-11:58 pm

1 stop7h 28m

$187

SpokaneSt. Louis

GEG - STL

GEGSTL

Spokane

sáb. 9/27

6:10 am-4:14 pm

1 stop8h 04m

Lambert-St Louis

mar. 9/30

7:40 am-11:55 am

1 stop6h 15m

$187

SpokaneChicago

GEG - ORD

GEGORD

Spokane

mar. 10/21

12:50 pm-11:40 pm

1 stop8h 50m

Chicago O'Hare Intl

vie. 10/24

6:55 pm-11:50 pm

1 stop6h 55m

$194

SpokaneChicago

GEG - ORD

GEGORD

Spokane

mié. 11/5

6:32 am-8:01 pm

1 stop11h 29m

Chicago O'Hare Intl

sáb. 11/8

10:30 am-12:32 pm

Nonstop4h 02m

$195

SpokaneChicago

GEG - MDW

GEGMDW

Spokane

mié. 9/10

2:45 pm-5:10 am

1 stop12h 25m

Chicago Midway

lun. 9/15

1:25 pm-3:20 pm

Nonstop3h 55m

$197

SpokaneChicago

GEG - ORD

GEGORD

Spokane

jue. 10/16

6:10 am-5:20 pm

1 stop9h 10m

Chicago O'Hare Intl

mar. 10/21

6:00 pm-11:59 pm

1 stop7h 59m

$201

SpokaneChicago

GEG - ORD

GEGORD

Spokane

mié. 9/24

1:30 pm-7:18 pm

Nonstop3h 48m

Chicago O'Hare Intl

lun. 9/29

10:46 am-12:44 pm

Nonstop3h 58m

$202

SpokaneChicago

GEG - ORD

GEGORD

Spokane

vie. 10/24

11:15 pm-8:29 am

1 stop7h 14m

Chicago O'Hare Intl

lun. 10/27

2:20 pm-9:05 pm

1 stop8h 45m

$203

SpokaneChicago

GEG - MDW

GEGMDW

Spokane

lun. 9/8

6:10 am-7:45 pm

1 stop11h 35m

Chicago Midway

dom. 9/14

10:30 am-12:25 pm

Nonstop3h 55m

$206

SpokaneChicago

GEG - MDW

GEGMDW

Spokane

lun. 1/12

6:30 am-6:34 pm

2 stops10h 04m

Chicago Midway

lun. 1/19

6:45 pm-11:16 pm

1 stop6h 31m

$207

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/7

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, August is the cheapest month in which you can book a flight from Idaho to Illinois (average of $245). Flying from Idaho to Illinois in March is currently the most expensive (average of $321). 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 agosto 7, 2025.

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Idaho to Illinois as you normally would.

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 agosto 7, 2025.

The most flights from USID to USIL are scheduled on a Monday (10 on average). You will have fewer flight options on Sunday, which is when the least amount of flights are scheduled (8 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 agosto 7, 2025.
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
10,000 reviews

Overall

8.0

Boarding

8.1

Comfort

7.8

Crew

8.5

Food

7.1

Entertainment

7.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2025

BOI - LAX

flying in first class, my husband froze the entire flight and was miserable. first class does not offer blankets or any entertainment. (TV etc)
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Boarding

8.1

Comfort

7.8

Crew

8.5

Food

7.1

Entertainment

7.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2025

BOI - LAX

flying in first class, my husband froze the entire flight and was miserable. first class does not offer blankets or any entertainment. (TV etc)
Southwest
8.0
Very good
4,247 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Boarding

8.1

Comfort

7.8

Crew

8.5

Food

7.1

Entertainment

7.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2025

BOI - LAX

flying in first class, my husband froze the entire flight and was miserable. first class does not offer blankets or any entertainment. (TV etc)
Delta
8.0
Very good
7,987 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Boarding

8.1

Comfort

7.8

Crew

8.5

Food

7.1

Entertainment

7.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2025

BOI - LAX

flying in first class, my husband froze the entire flight and was miserable. first class does not offer blankets or any entertainment. (TV etc)
Hawaiian Airlines
7.8
Good
2,631 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Boarding

8.1

Comfort

7.8

Crew

8.5

Food

7.1

Entertainment

7.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2025

BOI - LAX

flying in first class, my husband froze the entire flight and was miserable. first class does not offer blankets or any entertainment. (TV etc)
United Airlines
7.4
Good
8,916 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Boarding

8.1

Comfort

7.8

Crew

8.5

Food

7.1

Entertainment

7.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2025

BOI - LAX

flying in first class, my husband froze the entire flight and was miserable. first class does not offer blankets or any entertainment. (TV etc)

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.

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

    $55 is the cheapest one-way deal found within the past few days, from Spirit Airlines. You may also be able to find cheap deals on American Airlines and United Airlines, with prices starting from $65 and $71, 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, August is the cheapest month in which you can book a flight from Idaho to Illinois (average of $245). Flying from Idaho to Illinois in March is currently the most expensive (average of $321). 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

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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 agosto 7, 2025.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$139Average$358FlexibilityNo cancel feeOn-timeN/A
Alaska AirlinesCheapest$217Average$327FlexibilityNo cancel feeOn-time75%
SouthwestCheapest$233Average$386FlexibilityNo cancel feeOn-time63%
United AirlinesCheapest$239Average$567FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$247Average$506FlexibilityNo cancel feeOn-time71%

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