Boulder was named for the massive rocks scattered about the valley. First established in the 1860s as a stage station on the Fort Benton - Virginia City route, it later became a trading center for mining and agricultural areas. The Great Northern Railroad made its way through in 1888. By 1892, schools for the deaf, blind, and feeble-minded were established in Boulder. As early as the 1880s Boulder Hot Springs, a 52-room Spanish mission-style hotel, attracted tourists and weekenders to its spa resort. The facilities began as a modest boarding house for Northern Pacific railroad workers and travelers. C. W. Kerrick, a contractor who laid the Gallatin-Butte line, recognized the commercial value of the hot springs, so he leased the property from owner A. C. Qaintance, and built the grand hotel. Today, portions of the hotel have been renovated and are open for public use. Boulder’s most prominent landmark is the Jefferson County Courthouse, built in 1889. It is listed on the National Register of Historic Places. The building has a three-story entry and gargoyles perched on 24-inch thick stone walls.

Visit nearby Elkhorn State Park for excellent examples of frontier architecture. This ghost town stands as a reminder of Montana’s 1880s silver boom. Enjoy hiking and picnicking in this area.