Great Falls, MT is currently using only one area code which is area code 406. Area code 406 covers the entire state of Montana, including Billings, and was put into service on January 1, 1947.
In addition to Great Falls, MT area code 406 serves the larger cities and communities of Billings, Bozeman, Butte, Great Falls, Helena, Kalispell and Missoula in addition to many smaller communities in Montana.
Great Falls, MT is located in Cascade County and observes the Mountain Time Zone. View our Times by Area Code tool.