This is a list of properties and historic districts in Montana that are listed on the National Register of Historic Places. The state's more than 1,100 listings are distributed across all of its 56 counties.

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.