Jefferson County, Montana
|Jefferson County, Montana|
Location in the state of Montana
Montana's location in the U.S.
1,659 sq mi (4,297 km²)
1,657 sq mi (4,292 km²)
2 sq mi (5 km²), 0.13%
5/sq mi (2/km²)
According to the U.S. Census Bureau, the county has a total area of 1,659 miles (2,670 km). Of this total, 1,657 miles (2,667 km) of it is land, and 2 square miles (5.2 km2) of it (0.13%) is water.
Major highways 
- Interstate 90
- Interstate 15
- U.S. Highway 12
- U.S. Highway 287
- Montana Highway 2
- Montana Highway 41
- Montana Highway 55
- Montana Highway 69
Adjacent counties 
- Lewis and Clark County, Montana - north
- Broadwater County, Montana - east
- Gallatin County, Montana - southeast
- Madison County, Montana - south
- Silver Bow County, Montana - west
- Deer Lodge County, Montana - west
- Powell County, Montana - northwest
||Powell County||Lewis and Clark County|
|Silver Bow County and Deer Lodge County||Broadwater County|
|Madison County||Gallatin County|
National protected areas 
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 according to Census 2000.
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.
Census-designated places 
Ghost town 
See also 
- List of cemeteries in Jefferson County, Montana
- List of lakes in Jefferson County, Montana
- List of mountains in Jefferson County, Montana
- National Register of Historic Places listings in Jefferson County, Montana