DescriptionBig Horn County was one of the 9 original counties established by the Montana territorial legislature in February 1865. Defined as all the territory not included in any of the other counties, it encompassed the entire eastern third of the territory. For administrative purposes, since there were no large towns in the region, it was attached to Gallatin County. Over the years, portions of the county were broken off to form new counties. In 1877, Big Horn County became known as Custer County. However, today’s Big Horn County, consisting primarily of the Crow Indian Reservation, was established in 1913, with Hardin as the county seat.Other Name(s)Custer CountyContributing InstitutionMontana Historical Society Library and ArchivesGeolocation[1] CountyBig Horn County
