Which  county located in the U.S. state of Montana is Brockton  a town in
Brockton, Montana Brockton is a town in Roosevelt County, Montana, United States. The population was 255 at the 2010 census.
Beaverhead County, Montana Beaverhead County is the largest county by area in the U.S. state of Montana. As of the 2010 census, the population was 9,246. Its county seat is Dillon. The county was founded in 1865.