Jefferson County is a

county A county is a geographic region of a country used for administrative or other purposes Chambers Dictionary, L. Brookes (ed.), 2005, Chambers Harrap Publishers Ltd, Edinburgh in certain modern nations. The term is derived from the Old French ...

Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columb ...

, United States. As of the 2020 census, the population was 12,085. Its

county seat A county seat is an administrative center, seat of government, or capital city of a county or civil parish. The term is in use in Canada, China, Hungary, Romania, Taiwan, and the United States. The equivalent term shire town is used in the US st ...

is Boulder. The county was created in 1865 and named for President

Thomas Jefferson Thomas Jefferson (April 13, 1743 – July 4, 1826) was an American statesman, diplomat, lawyer, architect, philosopher, and Founding Father who served as the third president of the United States from 1801 to 1809. He was previously the natio ...

. Jefferson County is part of the Helena, MT Micropolitan Statistical Area.

Geography

According to the

United States Census Bureau The United States Census Bureau (USCB), officially the Bureau of the Census, is a principal agency of the U.S. Federal Statistical System, responsible for producing data about the American people and economy. The Census Bureau is part of t ...

, the county has a total area of , of which is land and (0.2%) is water.

Major highways

Interstate 15 Interstate 15 (I-15) is a major Interstate Highway in the western United States, running through Southern California and the Intermountain West. I-15 begins near the Mexican border in San Diego County and stretches north to Alberta, Cana ...

* Interstate 90 * U.S. Highway 12 * U.S. Highway 287 * Montana Highway 2 * Montana Highway 41 *

Montana Highway 55 Highway 55 (MT 55) in the U.S. State of Montana is a route running in a northerly direction from an intersection with MT 41 about north of the small town of Silver Star. The highway extends approximately to an interchange with Interstate 90 (I ...

* Montana Highway 69

Adjacent counties

* 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

National protected areas

* Deerlodge National Forest (part) * Helena National Forest (part)

Politics

Demographics

2000 census

As of the

2000 United States census The United States census of 2000, conducted by the Census Bureau, determined the resident population of the United States on April 1, 2000, to be 281,421,906, an increase of 13.2 percent over the 248,709,873 people enumerated during the 1990 cen ...

, there were 10,049 people, 3,747 households, and 2,847 families in the county. The

population density Population density (in agriculture: Stock (disambiguation), standing stock or plant density) is a measurement of population per unit land area. It is mostly applied to humans, but sometimes to other living organisms too. It is a key geographical ...

was 6 people per square mile (2/km²). There were 4,199 housing units at an average density of 2 per square mile (1/km²). The racial makeup of the county was 96.07%

White White is the lightest color and is achromatic (having no hue). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully reflect and scatter all the visible wavelengths of light. White o ...

, 0.14%

Black Black is a color which results from the absence or complete absorption of visible light. It is an achromatic color, without hue, like white and grey. It is often used symbolically or figuratively to represent darkness. Black and white ...

African American African Americans (also referred to as Black Americans and Afro-Americans) are an ethnic group consisting of Americans with partial or total ancestry from sub-Saharan Africa. The term "African American" generally denotes descendants of ens ...

, 1.26% Native American, 0.42% Asian, 0.07%

Pacific Islander Pacific Islanders, Pasifika, Pasefika, or rarely Pacificers are the peoples of the Pacific Islands. As an ethnic/racial term, it is used to describe the original peoples—inhabitants and diasporas—of any of the three major subregions of O ...

, 0.38% from

other races Other often refers to: * Other (philosophy), a concept in psychology and philosophy Other or The Other may also refer to: Film and television * ''The Other'' (1913 film), a German silent film directed by Max Mack * ''The Other'' (1930 film), a ...

, and 1.66% from two or more races. 1.48% of the population were

Hispanic The term ''Hispanic'' ( es, hispano) refers to people, cultures, or countries related to Spain, the Spanish language, or Hispanidad. The term commonly applies to countries with a cultural and historical link to Spain and to viceroyalties forme ...

or Latino of any race. 22.9% were of German, 13.1% English, 12.9%

Irish Irish may refer to: Common meanings * Someone or something of, from, or related to: ** Ireland, an island situated off the north-western coast of continental Europe ***Éire, Irish language name for the isle ** Northern Ireland, a constituent unit ...

, 7.9%

Norwegian Norwegian, Norwayan, or Norsk may refer to: *Something of, from, or related to Norway, a country in northwestern Europe * Norwegians, both a nation and an ethnic group native to Norway * Demographics of Norway *The Norwegian language, including ...

and 5.3%

American ancestry American ancestry refers to people in the United States who self-identify their ancestral origin or descent as "American," rather than the more common officially recognized racial and ethnic groups that make up the bulk of the American peo ...

. There were 3,747 households, out of which 35.60% had children under the age of 18 living with them, 67.10% were married couples living together, 5.90% had a female householder with no husband present, and 24.00% were non-families. 20.20% of all households were made up of individuals, and 7.30% had someone living alone who was 65 years of age or older. The average household size was 2.62 and the average family size was 3.03. The county population contained 27.80% under the age of 18, 5.20% from 18 to 24, 26.80% from 25 to 44, 29.90% from 45 to 64, and 10.30% who were 65 years of age or older. The median age was 40 years. For every 100 females, there were 100.80 males. For every 100 females age 18 and over, there were 100.40 males. The median income for a household in the county was $41,506, and the median income for a family was $48,912. Males had a median income of $34,753 versus $25,011 for females. The

per capita income Per capita income (PCI) or total income measures the average income earned per person in a given area (city, region, country, etc.) in a specified year. It is calculated by dividing the area's total income by its total population. Per capita i ...

for the county was $18,250. About 6.70% of families and 9.00% of the population were below the

poverty line The poverty threshold, poverty limit, poverty line or breadline is the minimum level of income deemed adequate in a particular country. The poverty line is usually calculated by estimating the total cost of one year's worth of necessities for t ...

, including 10.40% of those under age 18 and 9.60% of those age 65 or over.

2010 census

As of the

2010 United States census The United States census of 2010 was the twenty-third United States national census. National Census Day, the reference day used for the census, was April 1, 2010. The census was taken via mail-in citizen self-reporting, with enumerators servi ...

, there were 11,406 people, 4,512 households, and 3,301 families residing in the county. The population density was . There were 5,055 housing units at an average density of . 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

, 17.2% were English, 10.8% were

, 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

, including 5.1% of those under age 18 and 8.6% of those age 65 or over.

Communities

Towns

* Boulder (county seat) *

Whitehall Whitehall is a road and area in the City of Westminster, Central London. The road forms the first part of the A3212 road from Trafalgar Square to Chelsea. It is the main thoroughfare running south from Trafalgar Square towards Parliament Sq ...

Census-designated places

* Basin * Cardwell * Clancy (includes Alhambra) * Elkhorn *

Jefferson City Jefferson City, informally Jeff City, is the capital of Missouri, United States. It had a population of 43,228 at the 2020 census, ranking as the 15th most populous city in the state. It is also the county seat of Cole County and the principa ...

* Montana City * Rader Creek * South Hills

Unincorporated communities

Amazon Amazon most often refers to: * Amazons, a tribe of female warriors in Greek mythology * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon River, in South America * Amazon (company), an American multinational technolog ...

* Bernice * Corbin * Elk Park * Homestake *

Leadville The City of Leadville is a statutory city that is the county seat, the most populous community, and the only incorporated municipality in Lake County, Colorado, United States. The city population was 2,602 at the 2010 census and an estimated ...

* La Hood Park *

Louisville Louisville ( , , ) is the largest city in the Commonwealth of Kentucky and the 28th most-populous city in the United States. Louisville is the historical seat and, since 2003, the nominal seat of Jefferson County, on the Indiana border. ...

* Pappas Place * Paul Place *

Piedmont it, Piemontese , population_note = , population_blank1_title = , population_blank1 = , demographics_type1 = , demographics1_footnotes = , demographics1_title1 = , demographics1_info1 = , demographics1_title2 ...

* Pipestone * Renova''Renova, Jefferson County MT'' Google Maps (accessed January 2, 2019)
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Former communities

Comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ...

* Wickes

References

External links

* {{authority control Montana counties 1865 establishments in Montana Territory Helena, Montana micropolitan area Populated places established in 1865