Jefferson County
County in Montana
Jefferson County is a county in Montana, United States. As of the 2020 census, the population was 12,085. Its county seat is Boulder. The county was created in 1865 and named for President Thomas Jefferson.
Jefferson County is part of the Helena,... Wikipedia
Cities: Boulder, Jefferson City, Clancy, and more
Population: 12,826 (2022)
County seat: Boulder
Area: 1,659 mi²