Dillon was founded in the Beaverhead Valley as a railroad town in 1880 by Union Pacific Railroad President Sidney Dillon. The town’s location was selected by the railroad because of its proximity to gold mines in the area.
The first ore discovered in the Dillon area was silver. Gold was first discovered at Grasshopper Creek in 1862, precipitating a flood of immigration to the area. The last real gold rush in the area occurred near Argenta in 1920 and lasted for 30 years.
Dillon served as a central location for transporting goods to nearby boomtowns such as Bannack, Argenta, Glen, and Virginia City. In 1881, Dillon became part of a contentious battle with Bannack to become the county seat of Beaverhead County. The first brick building in Dillon was built in 1882. In 1884, Dillon became an incorporated town and began building sidewalks and permanent dwellings for the residents.
While many of the gold mining towns around Dillon died, Dillon was able to thrive due to the railroad and talc mining in the area. A cattle industry was established in 1865. The agriculturally rich Beaverhead Valley became an ideal location for sheep ranching, introduced in 1869. Dillon was once the largest exporter of sheep wool in Montana.
The Montana Normal College was established as a teaching college in 1892, and is still functioning today, renowned for its Education program. A circus elephant named Old Pitt was struck by lightning in 1943 and is buried at the Dillon fairgrounds. Captain Joel Rude of the Montana National Guard crashed his F-106 into a grain elevator and died during a Labor Day Parade on September 3, 1979. A plaque in his honor is part of the Southwest Montana Veterans Memorial park in Dillon.