Beltrami County was established by an act of the state legislature on February 28, 1866. The county’s first post office was established at Red Lake in 1875, and the first homesteader was Joachim Cyr at Little Turtle Lake in 1877. Bemidji became the county seat in 1897 after defeating Buena Vista. The Beaux Arts-inspired brick-and-stone courthouse with a domed tower was designed by Kinney and Detweiler and built in 1902, and it has been listed on the National Register of Historic Places since May 26, 1988. The county’s borders changed several times: in 1866 it extended from a line drawn west from Lake Itasca to a north-south line between Cass Lake and Lake Winnibigoshish, with its northern border passing through Upper Red Lake and its western border on a line running through Ebro; in 1879 it was extended to the Canadian border, making it 153 miles long and 54 miles wide; the boundary changed again when Clearwater became a county in 1902 and when Lake of the Woods County was formed in 1923, and by 1923 it was very close to its present boundary.