# Lewis and Clark County, Montana

Lewis and Clark County is a county located in the U.S. state of Montana. As of the 2020 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.

## Geography

According to the United States Census Bureau, the county has a total area of 3,498 square miles (9,060 km$^2$), of which 3,459 square miles (8,960 km$^2$) is land and 39 square miles (100 km$^2$) (1.1%) is water.

### Major highways

* I-15
* US 12
* US 287
* MT 21
* MT 200
* S-279
* S-284
* S-434

### Adjacent counties

* Teton County - north
* Cascade County - east
* Meagher County - east
* Broadwater County - southeast
* Jefferson County - south
* Powell County - west
* Flathead County - northwest

### 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)

## Demographics
### 2020 census

As of the 2020 census, there were 70,973 people living in the county.

### 2010 census

As of the 2010 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/km$^2$). There were 30,180 housing units at an average density of 8.7 per square mile (3.4/km$^2$). 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.

## Politics

Lewis and Clark County leans slightly Republican, but it has voted for Democratic candidates three times since 1964. Bill Clinton won by nearly seven percentage points in 1992, but Bob Dole won by 130 votes in 1996. Barack Obama carried the county in 2008 but lost it to Mitt Romney in 2012. In recent elections, the county has voted Republican but only by narrow margins.
United States presidential election results for Lewis and Clark County, Montana :
| Year | Republican | Republican | Democratic | Democratic | Third party(ies) | Third party(ies) |
| Year | No. | % | No. | % | No. | % |
| 2024 | 21,479 | 50.82% | 19,085 | 45.16% | 1,699 | 4.02% |
| 2020 | 21,409 | 50.64% | 19,743 | 46.70% | 1,121 | 2.65% |
| 2016 | 16,895 | 47.87% | 14,478 | 41.02% | 3,923 | 11.11% |
| 2012 | 16,803 | 50.43% | 15,620 | 46.88% | 895 | 2.69% |
| 2008 | 14,966 | 45.31% | 17,114 | 51.82% | 949 | 2.87% |
| 2004 | 16,494 | 55.27% | 12,717 | 42.61% | 632 | 2.12% |
| 2000 | 15,091 | 55.34% | 9,982 | 36.61% | 2,196 | 8.05% |
| 1996 | 11,665 | 43.94% | 11,535 | 43.45% | 3,347 | 12.61% |
| 1992 | 9,351 | 35.72% | 11,117 | 42.47% | 5,711 | 21.82% |
| 1988 | 10,946 | 46.91% | 11,932 | 51.14% | 456 | 1.95% |
| 1984 | 13,569 | 59.97% | 8,768 | 38.75% | 289 | 1.28% |
| 1980 | 12,128 | 57.18% | 6,815 | 32.13% | 2,269 | 10.70% |
| 1976 | 10,155 | 54.84% | 8,118 | 43.84% | 244 | 1.32% |
| 1972 | 10,719 | 61.90% | 6,081 | 35.12% | 516 | 2.98% |
| 1968 | 7,979 | 56.53% | 5,379 | 38.11% | 757 | 5.36% |
| 1964 | 6,155 | 44.97% | 7,506 | 54.84% | 26 | 0.19% |
| 1960 | 7,260 | 54.65% | 6,008 | 45.22% | 17 | 0.13% |
| 1956 | 7,959 | 64.41% | 4,397 | 35.59% | 0 | 0.00% |
| 1952 | 7,663 | 62.58% | 4,563 | 37.26% | 20 | 0.16% |
| 1948 | 5,174 | 50.85% | 4,745 | 46.63% | 257 | 2.53% |
| 1944 | 4,482 | 48.41% | 4,737 | 51.17% | 39 | 0.42% |
| 1940 | 4,762 | 44.58% | 5,814 | 54.42% | 107 | 1.00% |
| 1936 | 2,951 | 33.82% | 5,614 | 64.34% | 160 | 1.83% |
| 1932 | 3,671 | 42.71% | 4,714 | 54.84% | 211 | 2.45% |
| 1928 | 4,441 | 57.35% | 3,278 | 42.33% | 25 | 0.32% |
| 1924 | 3,433 | 49.93% | 1,869 | 27.19% | 1,573 | 22.88% |
| 1920 | 4,348 | 62.90% | 2,413 | 34.91% | 152 | 2.20% |
| 1916 | 3,423 | 42.99% | 4,337 | 54.47% | 202 | 2.54% |
| 1912 | 1,062 | 24.50% | 1,505 | 34.72% | 1,768 | 40.78% |
| 1908 | 2,033 | 45.89% | 2,062 | 46.55% | 335 | 7.56% |
| 1904 | 2,505 | 54.60% | 1,543 | 33.63% | 540 | 11.77% |
| 1900 | 2,043 | 42.03% | 2,763 | 56.84% | 55 | 1.13% |
| 1896 | 1,057 | 21.07% | 3,939 | 78.53% | 20 | 0.40% |
| 1892 | 2,014 | 38.14% | 2,093 | 39.64% | 1,173 | 22.22% |

## Communities
### Cities

* Helena (county seat)
* East Helena

### Census-designated places

* Augusta
* Canyon Creek
* Craig
* Gilman
* Helena Valley Northeast
* Helena Valley Northwest
* Helena Valley Southeast
* Helena Valley West Central
* Helena West Side
* Lincoln
* Marysville
* Milford Colony
* Rimini
* Unionville
* Wolf Creek
* York

### Other unincorporated communities

* Austin
* Bald Butte
* Birdseye
* Canyon Ferry
* Dearborn (partially within Cascade County)
* Fort Harrison Army Air Park
* Four Range
* Frontier Town
* Gearing
* La Chapelle Place
* Nelson
* Silver City
* Stoner Place
* Weed
* Wilborn
* Winston

## Education

School districts include:
K-12 (Unified):
* East Helena K-12 Schools
* Lincoln K-12 Schools
High school:
* Augusta High School District
* Helena High School District
Elementary school:
* Auchard Creek Elementary School District
* Augusta Elementary School District
* Helena Elementary School District
* Trinity Elementary School District
* Wolf Creek Elementary School District

## 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.