Acton, MontanaActon is a census-designated place in northwestern Yellowstone County, Montana, United States. It has a postal ZIP code and lies along Montana Highway 3 northwest of the city of Billings, the county seat of Yellowstone County.HistoryActon is a small farming community which originated as a stop on the Great Northern Railroad. The post office was opened in 1910. Charles T. Robinson served as the original postmaster. The post office no longer exists.ClimateAccording to the Köppen Climate Classification system, Acton has a semi-arid climate, abbreviated "BSk" on climate maps.EducationThe school districts are Broadview Elementary School District and Broadview High School District.