kids encyclopedia robot

Lewis and Clark County, Montana facts for kids

Kids Encyclopedia Facts
Quick facts for kids
Lewis and Clark County
The "Sleeping Giant" formation north of Helena
The "Sleeping Giant" formation north of Helena
Official seal of Lewis and Clark County
Map of Montana highlighting Lewis and Clark County
Location within the U.S. state of Montana
Map of the United States highlighting Montana
Montana's location within the U.S.
Country  United States
State  Montana
Founded June 2, 1865
Named for Meriwether Lewis and William Clark
Seat Helena
Largest city Helena
 • Total 3,498 sq mi (9,060 km2)
 • Land 3,459 sq mi (8,960 km2)
 • Water 39 sq mi (100 km2)  1.1%
 • Total 70,973
 • Density 20.2896/sq mi (7.8339/km2)
Time zone UTC−7 (Mountain)
 • Summer (DST) UTC−6 (MDT)
Congressional district At-large
  • Montana county number 05

Lewis and Clark County is a county located in the U.S. state of Montana. As of the 2020 United States Census, the population was 70,973. Its county seat is Helena, the state capital. The numerical designation for Lewis and Clark County (used in the issuance of the state's license plates) is 5. The county was established on June 2, 1865 as one of the nine original counties of the Territory of Montana named Edgerton County in honor of Sidney Edgerton, first Governor of the Territory of Montana, and was renamed Lewis and Clark County on March 1, 1868 in honor of explorers Meriwether Lewis and William Clark.

Lewis and Clark County is part of the Helena, Montana Micropolitan Statistical Area.


According to the U.S. Census Bureau, the county has a total area of 3,948 square miles (10,230 km2), of which 3,459 square miles (8,960 km2) is land and 39 square miles (100 km2) (1.1%) is water.

Major highways

  • I-15.svg Interstate 15
  • US 12.svg U.S. Highway 12
  • US 287.svg U.S. Highway 287
  • MT-21.svg Montana Highway 21
  • MT-200.svg Montana Highway 200

Adjacent counties

National protected areas

  • Flathead National Forest (part)
  • Helena National Forest (part)
  • Lewis and Clark National Forest (part)
  • Lolo National Forest (part)
  • Rocky Mountain Front Conservation Area (part)


Historical population
Census Pop.
1870 5,040
1880 6,521 29.4%
1890 19,145 193.6%
1900 19,171 0.1%
1910 21,853 14.0%
1920 18,660 −14.6%
1930 18,224 −2.3%
1940 22,131 21.4%
1950 24,540 10.9%
1960 28,006 14.1%
1970 33,281 18.8%
1980 43,039 29.3%
1990 47,495 10.4%
2000 55,716 17.3%
2010 63,395 13.8%
2020 70,973 12.0%
US Decennial Census
1790-1960 1900-1990
1990-2000 2010-2020

2010 census

As of the 2010 United States Census, there were 63,395 people, 26,694 households, and 16,705 families in the county. The population density was 18.3 inhabitants per square mile (7.1/km2). There were 30,180 housing units at an average density of 8.7 per square mile (3.4/km2). The racial makeup of the county was 94.0% white, 2.1% American Indian, 0.6% Asian, 0.3% black or African American, 0.1% Pacific islander, 0.5% from other races, and 2.4% from two or more races. Those of Hispanic or Latino origin made up 2.5% of the population. In terms of ancestry, 29.2% were German, 19.3% were Irish, 15.0% were English, 8.9% were Norwegian, and 5.1% were American.

Of the 26,694 households, 28.8% had children under the age of 18 living with them, 49.0% were married couples living together, 9.4% had a female householder with no husband present, 37.4% were non-families, and 30.7% of all households were made up of individuals. The average household size was 2.30 and the average family size was 2.87. The median age was 40.9 years.

The median income for a household in the county was $50,238 and the median income for a family was $65,573. Males had a median income of $44,476 versus $34,893 for females. The per capita income for the county was $25,894. About 5.8% of families and 9.7% of the population were below the poverty line, including 10.2% of those under age 18 and 4.1% of those age 65 or over.




Census-designated places

Other unincorporated communities

Ghost town

Notable people

  • Seth Bullock, sheriff of Lewis and Clark County, later sheriff of Deadwood, South Dakota.
  • Ted Kaczynski, known as the Unabomber, lived in a cabin in Lincoln from 1971 to 1996, during which time he conducted his infamous bombing campaign.
  • Mike McGrath, Chief Justice of the Montana Supreme Court, former Montana Attorney General, former County Attorney of Lewis and Clark County.
  • Johnny Miljus, major league baseball pitcher, retired to Fort Harrison in Lewis and Clark County.
  • W. A. Boyle, president of the UMW, was born in Bald Butte, approximately two miles southwest of Marysville.
  • Brian Knight, Major League Baseball umpire
  • The governor of Montana, whose official residence is in the state capital of Helena.

See also

Kids robot.svg In Spanish: Condado de Lewis and Clark para niños

National Hispanic Heritage Month on Kiddle
Hispanic Hollywood icons
Myrtle Gonzalez
Rita Hayworth
Dolores del Río
Katy Jurado
kids search engine
Lewis and Clark County, Montana Facts for Kids. Kiddle Encyclopedia.