Cheap flights from Boise to Illinois from $131

The cheapest month to fly to Illinois from Boise is in February. Flight prices, which tend to average around $336, are often lower during this time because this is during the off-season. If you aren’t able to travel to Illinois during the month of February, then flying in August is also cheap. Prices for this month can be found on momondo for an average of $387.

The cheapest day to depart from Boise to Illinois is on a Thursday when prices can be found for as low as $513. Flights from Boise to Illinois on a Sunday will generally be more expensive and average around $740. Keep in mind that these prices on both days could fluctuate depending on the season and the demand.

Our most recent data shows that the best time of day to fly to Illinois is in the afternoon. Flights from Boise to Illinois during this time can be as low as $436. Flights in the morning are often more expensive with an average ticket price of $611.

Fly from Boise Air Term. Gowen Fld to Chicago O'Hare Intl for the best Boise Air Term. Gowen Fld - Illinois flight prices

You are more likely to see cheaper flights to Illinois from Boise when booking weeks ahead of your departure date. In general, you can expect to find flights to Illinois for around $417 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Illinois from Boise for as low as $331 on momondo.

There are 4 cabin classes available to choose from on Boise to Illinois flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Frontier, Alaska Airlines, and Southwest are the most popular carriers operating from Boise Air Term. Gowen Fld to Illinois

United Airlines, American Airlines and Delta are the top three most popular airlines that fly to Illinois from Boise according to our data. United Airlines is the first choice among our users, with 46% of people opting to fly with this airline when traveling to Illinois. Keep in mind that there are 5 different airlines that fly to Illinois on a routine basis, so you have a few additional options to choose from.

8 flights are operational daily from Boise to Illinois as of September 2026. The most popular departure time for this route is 12:00PM, with 66% of flights per day taking off in the afternoon.

As of September 2026, 62 flights take off from Boise and land in Illinois each week. The most common flight departure day for this route is Mon, with 16% of weekly flights taking off on this day.