Jefferson County | |
|---|---|
_-_Jefferson_County,_Montana.png) Jefferson County Courthouse in Boulder | |
 Location within the U.S. state of Montana | |
 Montana's location within the U.S. | |
| Coordinates: 46°11′N 112°07′W / 46.18°N 112.11°W | |
| Country |  United States |
| State |  Montana |
| Founded | February 2, 1865[1] |
| Named for | Thomas Jefferson |
| Seat | Boulder |
| Largest town | Clancy |
| Area | |
• Total | 1,659 sq mi (4,300 km2) |
| • Land | 1,656 sq mi (4,290 km2) |
| • Water | 2.6 sq mi (7 km2) 0.2% |
| Population (2020) | |
• Total | 12,085 |
• Estimate (2022) | 12,826  |
| • Density | 7/sq mi (3/km2) |
| Time zone | UTC−7 (Mountain) |
| • Summer (DST) | UTC−6 (MDT) |
| Congressional district | 2nd |
| Website | www |
| |
Jefferson County is a county in Montana, United States. As of the 2020 census, the population was 12,085.[2] Its county seat is Boulder.[3] The county was created in 1865[4] and named for President Thomas Jefferson.[5]
Jefferson County is part of the Helena, MT Micropolitan Statistical Area.
- ^ "Montana County Formation Table". genealogytrails.com. Retrieved April 3, 2018.
- ^ "State & County QuickFacts". United States Census Bureau. Retrieved May 8, 2023.
- ^ "Find a County". National Association of Counties. Archived from the original on May 31, 2011. Retrieved June 7, 2011.
- ^ "Montana Place Names Companion". Montana Place Names From Alzada to Zortman. Montana Historical Society Research Center. Retrieved December 1, 2014.
- ^ Gannett, Henry (1905). The Origin of Certain Place Names in the United States. Govt. Print. Off. p. 168.