Cheap flights from Montreal to Illinois from C$ 243

In general, February is the cheapest month to fly from Montreal to Illinois. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around C$ 71. If you don’t want to visit Illinois in February, then you should wait until October to fly from Montreal, when ticket prices are also cheap, with an average price of C$ 73.

According to our data, Thursday is the cheapest day to fly to Illinois from Montreal. The lowest ticket price found for a Thursday departure recently was C$ 713. Keep in mind that prices can always vary depending on your route and whether or not you are flying domestic or international. The most expensive day to fly to Illinois is Sunday, with ticket prices averaging around C$ 1,092.

Our most recent data shows that the best time of day to fly to Illinois is in the afternoon. Flights from Montreal to Illinois during this time can be as low as C$ 748. If you have a flexible travel schedule, then try to avoid flying at noon when prices are C$ 1,191 on average. Flights to Illinois from Montreal at noon are generally more expensive because this time of day is more convenient for travellers’ schedules.

Fly from Montreal Pierre Elliott Trudeau Intl to Chicago O'Hare Intl for the best Montreal - Illinois flight prices

You are more likely to see cheaper flights to Illinois from Montreal when booking weeks ahead of your departure date. In general, you can expect to find flights to Illinois for around C$ 495 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Illinois from Montreal for as low as C$ 334 on momondo.

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

United Airlines, Porter Airlines, and Delta are the most popular carriers operating from Montreal to Illinois

Air Canada, United Airlines and Porter Airlines are the top three most popular airlines that fly to Illinois from Montreal according to our data. Air Canada is the first choice among our users, with 65% of people opting to fly with this airline when travelling to Illinois. Keep in mind that there are 4 different airlines that fly to Illinois on a routine basis, so you have a few additional options to choose from.

The number of flights available between Montreal and Illinois is 32 per day as of June 2026. The most frequent departure time is 6:00a.m., with 51% of daily flights leaving in the afternoon.

The number of flights available between Montreal and Illinois is 229 per week as of June 2026. The most frequent departure day is Wed, with 15% of weekly flights leaving on this day.