Boulder is a town in and the county seat of Jefferson County, Montana. It is located at the junction of Interstate 15 and Montana Highway 69. It is part of the Helena Micropolitan Statistical Area, and its population at the 2000 census was 1,300.
After establishment, the town became a regional trading center for farmers, ranchers, and miners and, by the end of the twentieth century, home to state schools for the deaf, blind and developmentally disabled.
Currently, many people are employed in Boulder at the Montana Developmental Center, a state institution for people with developmental disabilities. Some work for Alternative Youth Adventures, which provides services for troubled youth. In addition, Riverside Corrections, a state-run detention center for juvenile females, employs about 30 people. Boulder is also popular for its "health mines" (which are controversial in nature).
The town has a large community library, two weekly newspapers and a local radio station. Three buildings in Boulder are on the National Register of Historic Places.
The population predominantly comprises White Americans. A small percentage of the population comprises people of Hispanic origin, as well as Native Americans.