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Jefferson County
Jefferson County Courthouse in Boulder
Map of Montana highlighting Jefferson County
Location within the U.S. state of Montana
Map of the United States highlighting Montana
Montana's location within the U.S.
Coordinates: 46°11′N 112°07′W / 46.18°N 112.11°W / 46.18; -112.11
Country United States
State Montana
FoundedFebruary 2, 1865[1]
Named forThomas Jefferson
SeatBoulder
Largest townClancy
Area
 • Total1,659 sq mi (4,300 km2)
 • Land1,656 sq mi (4,290 km2)
 • Water2.6 sq mi (7 km2)  0.2%
Population
 (2020)
 • Total12,085
 • Estimate 
(2022)
12,826 Increase
 • Density7/sq mi (3/km2)
Time zoneUTC−7 (Mountain)
 • Summer (DST)UTC−6 (MDT)
Congressional district2nd
Websitewww.jeffersoncounty-mt.gov
  • Montana county number 51

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.

Geography[edit]

According to the United States Census Bureau, the county has a total area of 1,659 square miles (4,300 km2), of which 1,656 square miles (4,290 km2) is land and 2.6 square miles (6.7 km2) (0.2%) is water.[6]

Major highways[edit]

Adjacent counties[edit]

National protected areas[edit]

Politics[edit]

United States presidential election results for Jefferson County, Montana[7]
Year Republican Democratic Third party
No.  % No.  % No.  %
2020 5,345 65.57% 2,625 32.20% 181 2.22%
2016 4,177 62.21% 1,998 29.76% 539 8.03%
2012 4,055 62.18% 2,272 34.84% 194 2.98%
2008 3,538 55.80% 2,582 40.72% 221 3.49%
2004 3,844 65.51% 1,881 32.06% 143 2.44%
2000 3,308 64.07% 1,513 29.30% 342 6.62%
1996 2,248 46.82% 1,775 36.97% 778 16.20%
1992 1,541 36.47% 1,415 33.49% 1,269 30.04%
1988 2,007 52.31% 1,746 45.50% 84 2.19%
1984 2,226 61.53% 1,324 36.59% 68 1.88%
1980 1,841 57.12% 1,055 32.73% 327 10.15%
1976 1,387 52.26% 1,210 45.59% 57 2.15%
1972 1,281 56.06% 904 39.56% 100 4.38%
1968 798 45.06% 820 46.30% 153 8.64%
1964 662 40.59% 967 59.29% 2 0.12%
1960 817 51.38% 769 48.36% 4 0.25%
1956 1,049 61.38% 660 38.62% 0 0.00%
1952 1,084 60.76% 687 38.51% 13 0.73%
1948 750 45.62% 836 50.85% 58 3.53%
1944 797 49.72% 803 50.09% 3 0.19%
1940 830 39.58% 1,259 60.04% 8 0.38%
1936 573 27.78% 1,409 68.30% 81 3.93%
1932 784 37.09% 1,246 58.94% 84 3.97%
1928 1,013 56.97% 751 42.24% 14 0.79%
1924 648 36.49% 434 24.44% 694 39.08%
1920 969 54.47% 688 38.67% 122 6.86%
1916 712 36.63% 1,124 57.82% 108 5.56%
1912 239 20.03% 479 40.15% 475 39.82%
1908 546 39.22% 714 51.29% 132 9.48%
1904 663 45.54% 580 39.84% 213 14.63%

Demographics[edit]

Historical population
CensusPop.Note
18701,531
18802,46460.9%
18906,026144.6%
19005,330−11.5%
19105,6015.1%
19205,203−7.1%
19304,133−20.6%
19404,66412.8%
19504,014−13.9%
19604,2977.1%
19705,23821.9%
19807,02934.2%
19907,93912.9%
200010,04926.6%
201011,40613.5%
202012,0856.0%
2022 (est.)12,826[8]6.1%
U.S. Decennial Census[9]
1790–1960,[10] 1900–1990,[11]
1990–2000,[12] 2010–2020[2]

2020 census[edit]

As of the 2020 census, there were 12,085 people living in the county.[13]

2010 census[edit]

As of the 2010 census, there were 11,406 people, 4,512 households, and 3,301 families residing in the county. The population density was 6.9 inhabitants per square mile (2.7/km2). There were 5,055 housing units at an average density of 3.1 per square mile (1.2/km2). The racial makeup of the county was 95.5% white, 1.4% American Indian, 0.4% Asian, 0.1% black or African American, 0.4% from other races, and 2.2% from two or more races. Those of Hispanic or Latino origin made up 2.0% of the population. In terms of ancestry, 31.3% were German, 19.1% were Irish, 17.2% were English, 10.8% were Norwegian, and 4.2% were American.

Of the 4,512 households, 28.8% had children under the age of 18 living with them, 63.7% were married couples living together, 5.4% had a female householder with no husband present, 26.8% were non-families, and 22.6% of all households were made up of individuals. The average household size was 2.48 and the average family size was 2.90. The median age was 46.2 years.

The median income for a household in the county was $56,695 and the median income for a family was $67,195. Males had a median income of $50,978 versus $34,148 for females. The per capita income for the county was $26,437. About 2.7% of families and 12.8% of the population were below the poverty line, including 5.1% of those under age 18 and 8.6% of those age 65 or over.

Communities[edit]

Towns[edit]

Census-designated places[edit]

Unincorporated communities[edit]

Former communities[edit]

See also[edit]

References[edit]

  1. ^ "Montana County Formation Table". genealogytrails.com. Retrieved April 3, 2018.
  2. ^ a b "State & County QuickFacts". United States Census Bureau. Retrieved May 8, 2023.
  3. ^ "Find a County". National Association of Counties. Archived from the original on May 31, 2011. Retrieved June 7, 2011.
  4. ^ "Montana Place Names Companion". Montana Place Names From Alzada to Zortman. Montana Historical Society Research Center. Retrieved December 1, 2014.
  5. ^ Gannett, Henry (1905). The Origin of Certain Place Names in the United States. Govt. Print. Off. p. 168.
  6. ^ "2010 Census Gazetteer Files". United States Census Bureau. August 22, 2012. Archived from the original on December 5, 2014. Retrieved November 28, 2014.
  7. ^ Leip, David. "Atlas of US Presidential Elections". uselectionatlas.org. Retrieved April 3, 2018.
  8. ^ "Annual Estimates of the Resident Population for Counties: April 1, 2020 to July 1, 2022". United States Census Bureau. Retrieved May 8, 2023.
  9. ^ "U.S. Decennial Census". United States Census Bureau. Retrieved November 28, 2014.
  10. ^ "Historical Census Browser". University of Virginia Library. Retrieved November 28, 2014.
  11. ^ "Population of Counties by Decennial Census: 1900 to 1990". United States Census Bureau. Retrieved November 28, 2014.
  12. ^ "Census 2000 PHC-T-4. Ranking Tables for Counties: 1990 and 2000" (PDF). United States Census Bureau. Archived (PDF) from the original on March 27, 2010. Retrieved November 28, 2014.
  13. ^ "Jefferson County, Montana". United States Census Bureau. Retrieved February 29, 2024.
  14. ^ Amazon, Jefferson County MT Google Maps (accessed January 2, 2019)
  15. ^ Bernice, Jefferson County MT Google Maps (accessed January 2, 2019)
  16. ^ Elk Park, Jefferson County MT Google Maps (accessed January 2, 2019)
  17. ^ Homestake, Jefferson County MT Google Maps (accessed January 2, 2019)
  18. ^ Leadville, Jefferson County MT Google Maps (accessed January 2, 2019)
  19. ^ La Hood Park, Jefferson County MT Google Maps (accessed January 2, 2019)
  20. ^ Louisville, Jefferson County MT Google Maps (accessed January 2, 2019)
  21. ^ Pappas Place, Jefferson County MT Google Maps (accessed January 2, 2019)
  22. ^ Paul Place, Jefferson County MT Google Maps (accessed January 2, 2019)
  23. ^ Piedmont, Jefferson County MT Google Maps (accessed January 2, 2019)
  24. ^ Pipestone, Jefferson County MT Google Maps (accessed January 2, 2019)
  25. ^ Renova, Jefferson County MT Google Maps (accessed January 2, 2019)

External links[edit]