Jefferson County, Montana facts for kids

Kids Encyclopedia Facts
Jefferson County, Montana
Map

Location in the state of Montana
Map of the USA highlighting Montana
Montana's location in the U.S.
Statistics
Founded February 2, 1865
Seat Boulder
Largest town Boulder
Area
 - Total
 - Land
 - Water

1,659 sq mi (4,297 km²)
1,656 sq mi (4,289 km²)
2.6 sq mi (7 km²), 0.2%
PopulationEst.
 - (2015)
 - Density

11,645
6.9/sq mi (3/km²)
Time zone Mountain: UTC-7/-6
Website: http://www.jeffersoncounty-mt.gov/
Named for: Thomas Jefferson

Jefferson County is a county located in the U.S. state of Montana. As of the 2010 census, the population was 11,406. Its county seat is Boulder. The county was created in 1865 and named for President Thomas Jefferson.

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

Geography

According to the U.S. 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.

Major highways

  • I-90.svg Interstate 90
  • I-15.svg Interstate 15
  • US 12.svg U.S. Highway 12
  • US 287.svg U.S. Highway 287
  • MT-2.svg Montana Highway 2
  • MT-41.svg Montana Highway 41
  • MT-55.svg Montana Highway 55
  • MT-69.svg Montana Highway 69

Adjacent counties

National protected areas

  • Deerlodge National Forest (part)
  • Helena National Forest (part)

Demographics

Historical population
Census Pop.
1870 1,531
1880 2,464 60.9%
1890 6,026 144.6%
1900 5,330 −11.5%
1910 5,601 5.1%
1920 5,203 −7.1%
1930 4,133 −20.6%
1940 4,664 12.8%
1950 4,014 −13.9%
1960 4,297 7.1%
1970 5,238 21.9%
1980 7,029 34.2%
1990 7,939 12.9%
2000 10,049 26.6%
2010 11,406 13.5%
Est. 2015 11,645 2.1%
U.S. Decennial Census
1790-1960 1900-1990
1990-2000 2010-2015

2000 census

As of the census of 2000, there were 10,049 people, 3,747 households, and 2,847 families residing in the county. The population density 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, 0.14% Black or African American, 1.26% Native American, 0.42% Asian, 0.07% Pacific Islander, 0.38% from other races, and 1.66% from two or more races. 1.48% of the population were Hispanic or Latino of any race. 22.9% were of German, 13.1% English, 12.9% Irish, 7.9% Norwegian and 5.3% American ancestry.

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.

In the county, the population was spread out with 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 for the county was $18,250. About 6.70% of families and 9.00% of the population were below the poverty line, 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, 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

Towns

Census-designated places

Ghost towns


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