3 hr 45 min is the shortest flight time from Chicago to Las Vegas.

The cheapest days to fly are usually in October. Typical prices range from $90 to $165.

The best round-trip deal recently found on Google Flights from Chicago to Las Vegas was with Frontier from $38. The best one-way deal was with Frontier from $19.

There are direct flights from Chicago to Las Vegas on a daily basis.

Southwest, Frontier, United, American and Spirit fly direct from Chicago to Las Vegas.

The cheapest round-trip flight from Chicago to Las Vegas starts at $38 from Sat, Sep 14 to Fri, Sep 20. The cheapest one-way flight starts at $19 and departs on Wed, Sep 11.

Las Vegas is a busy year-round destination with a subtropical desert climate. There's no specific peak season, but crowds and prices increase around holidays and the many annual conventions. Popular events include the Consumer Electronic Show (Jan), the Project fashion trade show (Feb and Aug), NASCAR Weekend (Mar), the National Finals Rodeo (Dec), and New Year's Eve. During summer (Jun–Aug), extremely high daytime temperatures may make outdoor activities like golf and canyon hiking inadvisable.

It's easy to use Google Flights to find the cheapest days to fly from Chicago to Las Vegas.
Just click the Departure label near the top of the page to open the calendar. Choose a start date and a return date to see how the round-trip fare changes on those specific days.
Adjust the trip type to see one-way fares. The cheapest available flights are highlighted and easy to spot. Once you settle on dates, click the Search button to see flight options and book the deal.

You can also turn on price tracking to get alerts if the price changes for a route or flight.