Hardin is a city in and the county seat of Big Horn County, Montana, United States. The population was 3,505 at the 2010 census.
It is located just north of the Crow Indian Reservation.
The city was named for Samuel Hardin, a friend of developer Charles Henry Morrill. It was incorporated in 1911. Thomas D. Campbell operated the nation’s largest wheat farm on 95,000 acres near here and pioneered the use of industrial machinery in farming. The Holly Sugar Company established a sugar beet–processing plant in Hardin in 1937.
Hardin is located at 45°43′55″N 107°36′45″W (45.731824, -107.612542).
According to the United States Census Bureau, the city has a total area of 2.57 square miles (6.66 km2), all land.
The Little Bighorn River empties into the Bighorn River near the town.
Hardin hosts a bitcoin mining facility by Marathon Patent Group, according to a press release by the company.
As of the census of 2010, there were 3,505 people, 1,301 households, and 850 families living in the city. The population density was 1,363.8 inhabitants per square mile (526.6/km2). There were 1,401 housing units at an average density of 545.1 per square mile (210.5/km2).