From the 16th to the late 19th centuries Valley County was inhabited by Indians due to the bounty of Buffalo and Pronghorn Antelope that provided ample food for the tribes. In 1804 the Lewis and Clark expedition came within 15 miles of the future site of the city of Glasgow (Valley County Seat) and took note of the ample herds of buffalo and other game. In 1887 a treaty was signed where the tribes surrendered 17.5 million acres, which led from 1888 to the formation of the Fort Peck Indian Reservation.  Valley County is the fourth-largest county in Montana (by land area) It is home to approximately 7,369 residents.

Not including unincorporated communities