Jefferson County, Montana

Jefferson County is a slice of Big Sky Country in southwestern Montana. Boulder serves as the county seat, a small town known for its seriously hot springs. The county has a split personality: part mountainous wilderness and part river valleys.

The Elkhorn Mountains rise to the east, while the Continental Divide follows the western border. Talk about being caught between a rock and a hard place. The Boulder River winds through the landscape as a blue-ribbon trout stream that can make any angler’s heart skip a beat.

Ranching is still a way of life here, but don’t let that fool you. A growing tech scene is also taking shape. Summers are beautiful but short, while winters are definitely not for the faint of heart. But if you can handle the cold, you’ll be rewarded with some of the most stunning scenery Montana has to offer.

CategoryDetails
County NameJefferson County
County SeatBoulder
EtymologyNamed after Thomas Jefferson, the third President of the United States
Cities, Towns, and CommunitiesBoulder, Whitehall, Clancy, Montana City, Basin
Interstates and HighwaysI-15, US 287, MT 2
FIPS Code30-043
Total Area (Land and Water)1,660 square miles (Land: 1,656 sq mi, Water: 4 sq mi)
Adjacent Counties (and Direction)Lewis and Clark County (North), Broadwater County (East), Gallatin County (Southeast), Madison County (South), Silver Bow County (West), Deer Lodge County (West), Powell County (Northwest)
Time ZoneMountain Time Zone (MT)
StateMontana
Coordinates46.2667° N, 112.1008° W
Major LandmarksElkhorn Mountains, Lewis and Clark Caverns State Park, Jefferson River
PopulationApproximately 12,500
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