Welcome to Jefferson County ...

Time Zone: Jefferson County lies in the Mountain Time Zone (MST/MDT) and observes daylight saving time.

The community of Boulder is the Seat for Jefferson County.

Jefferson County is one of the original counties of Montana and was founded in 1864.

From the Census Estimates for 2019, <1> Jefferson had a population of 12,221 people. This is an increase of 7.14% since the last Census (which gave a population of 11,407 people in 2010).

At the time of the 2010 Census, Jefferson represented 1.15% of the total population of Montana.

Websites of Interest ...

• Websites specific to Montana
  • Jump to Cyndi's List
  • Jump to Family Search
  • Jump to Genealogy Trails
  • Website for the Montana Historical Society

• Websites specific to Jefferson County
  • Jump to Cyndi's List
  • Jump to Family Search
  • Jump to Genealogy Trails

• Websites for nearby counties
  • Broadwater County
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  • Deer Lodge County
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  • Gallatin County
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  • Lewis and Clark County
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  • Madison County
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  • Powell County
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  • Silver Bow County
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    • Jump to Genealogy Trails

• Cemetery Information and Directories
  • Cyndi's List
  • Cemeteries of Montana
  • Cemeteries of Jefferson County
  • FamilySearch.org: Cemeteries of Montana
  • Find-A-Grave: Home Page
  • Interment.net
  • Cemeteries of Montana
  • Cemeteries of Jefferson County