Jefferson County is a

county A county () is a geographic region of a country used for administrative or other purposesL. Brookes (ed.) '' Chambers Dictionary''. Edinburgh: Chambers Harrap Publishers Ltd, 2005. in some nations. The term is derived from the Old French denoti ...

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...

, 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 parish (administrative division), civil parish. The term is in use in five countries: Canada, China, Hungary, Romania, and the United States. An equiva ...

Boulder In geology, a boulder (or rarely bowlder) is a rock fragment with size greater than in diameter. Smaller pieces are called cobbles and pebbles. While a boulder may be small enough to move or roll manually, others are extremely massive. In ...

. The county was created in 1865 and named for President

Thomas Jefferson Thomas Jefferson (, 1743July 4, 1826) was an American Founding Fathers of the United States, Founding Father and the third president of the United States from 1801 to 1809. He was the primary author of the United States Declaration of Indepe ...

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

Geography

According to the

United States Census Bureau The United States Census Bureau, officially the Bureau of the Census, is a principal agency of the Federal statistical system, U.S. federal statistical system, responsible for producing data about the American people and American economy, econ ...

, 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, Ca ...

Interstate 90 Interstate 90 (I-90) is an east–west transcontinental freeway and the longest Interstate Highway in the United States at . It begins in Seattle, Washington, and travels through the Pacific Northwest, Mountain states, Mountain West, Great Pla ...

* 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 - 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

2020 census

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

2010 census

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 . 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 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 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 ...

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

Communities

Towns

(county seat) *

Whitehall Whitehall is a road and area in the City of Westminster, Central London, England. The road forms the first part of the A roads in Zone 3 of the Great Britain numbering scheme, A3212 road from Trafalgar Square to Chelsea, London, Chelsea. It ...

Census-designated places

* Basin * Cardwell * Clancy (includes

Alhambra The Alhambra (, ; ) is a palace and fortress complex located in Granada, Spain. It is one of the most famous monuments of Islamic architecture and one of the best-preserved palaces of the historic Muslim world, Islamic world. Additionally, the ...

) * Elkhorn *

Jefferson City Jefferson City, informally Jeff City, is the List of capitals in the United States, capital of the U.S. state of Missouri. It had a population of 43,228 at the 2020 United States census, ranking as the List of cities in Missouri, 16th most popu ...

* Montana City * Rader Creek * South Hills

Unincorporated communities

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

* Bernice * Corbin * Elk Park * Homestake *

Leadville Leadville ( ) is a List of municipalities in Colorado#Statutory city, statutory city that is the county seat, the most populous community, and the only List of municipalities in Colorado, incorporated municipality in Lake County, Colorado, Lak ...

* La Hood Park *

Louisville Louisville is the most populous city in the Commonwealth of Kentucky, sixth-most populous city in the Southeast, and the 27th-most-populous city in the United States. By land area, it is the country's 24th-largest city; however, by populatio ...

* Pappas Place * Paul Place *

Piedmont Piedmont ( ; ; ) is one of the 20 regions of Italy, located in the northwest Italy, Northwest of the country. It borders the Liguria region to the south, the Lombardy and Emilia-Romagna regions to the east, and the Aosta Valley region to the ...

* Pipestone * Renova

Former communities

Comet A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or Coma (cometary), coma surrounding ...

* Wickes

Education

References

External links

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