Jefferson County MT

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.
  • Country: United States
  • State: Montana
  • Founded: February 2, 1865
  • Named for: Thomas Jefferson
  • Seat: Boulder
  • Largest town: Clancy
  • Congressional district: 2nd
Data from: en.wikipedia.org