Phillips County is a county in the U.S. state of Montana. As of the 2020 census, the population was 4,217. Its county seat is Malta. Before February 5, 1915, Phillips County was part of Blaine County, and before 1912 both were part of Chouteau County. It was named for rancher and state senator Benjamin D. Phillips.

Blaine County is a county in the U.S. state of Montana. As of the 2020 census, the population was 7,044. Its county seat is Chinook. The county was named for James G. Blaine, former United States Secretary of State. It is on the north line of the state, and thus shares the southern border of Canada opposite Saskatchewan.