Lewis and Clark County, Montana Population 2026

Updated April 2026 · US Census ACS 2023 5-Year Estimates · 6th-largest in Montana

The population of Lewis and Clark County, Montana is 72,580 as of the 2023 American Community Survey, making it the 6th-largest county in Montana. The median household income is $74,543, the median home value is $358,200, and the median age is 41.3.

The population of Lewis and Clark County has grown 18.2% since 2010 (63,578 → 75,129), a +1.20% annualized rate.

Lewis and Clark County within Montana · Source: US Census TIGER/Line via us-atlas

72,580

Population

+1.20%

Annual growth

People / sq mi

$74,543

Median Income

$358,200

Median Home Value

Lewis and Clark County covers 3,458 sq mi of land at 21.0 people per square mile.

About Lewis and Clark County, MT

Lewis and Clark County is a county in Montana with a population of 72,580. It ranks #6 among counties in Montana by population. The median age is 41.3, older than the national median. The population is 49.7% male and 50.3% female.

The median household income in Lewis and Clark County is $74,543, near the US median of $74,580. 4.4% of residents live below the federal poverty level. Home values sit at a median of $358,200, with monthly rent averaging $1,062. The homeownership rate of 69.7% is higher than the national rate of 64.8%.

Educational attainment in Lewis and Clark County reflects 42.8% of adults 25 and older holding a bachelor's degree or higher, above the national average of 34.3%. Roughly 12.9% of workers primarily work from home, similar to the national work-from-home rate of 14.2%. The average commute is 17.5 minutes each way.

Lewis and Clark County Population History (2010-2024)

The county of Lewis and Clark County had a population of 63,578 in 2010 and 75,129 in 2024, a 18.2% growth over 14 years. The peak was 75,129 in 2024. Average annual growth rate: 1.20%.

75,129

Population (2024)

63,578

Population (2010)

75,129

Peak (2024)

1.20%

Avg Annual Growth

Year	Population	Change	Annual %	Source
2010	63,578	-	-	estimate
2011	64,284	+706	+1.11%	estimate
2012	64,760	+476	+0.74%	estimate
2013	65,277	+517	+0.80%	estimate
2014	65,764	+487	+0.75%	estimate
2015	66,308	+544	+0.83%	estimate
2016	67,001	+693	+1.05%	estimate
2017	67,988	+987	+1.47%	estimate
2018	68,775	+787	+1.16%	estimate
2019	69,578	+803	+1.17%	estimate
2020	71,179	+1,601	+2.30%	estimate
2021	72,517	+1,338	+1.88%	estimate
2022	73,681	+1,164	+1.61%	estimate
2023	74,812	+1,131	+1.53%	estimate
2024	75,129	+317	+0.42%	estimate

Race & Ethnicity

White	91.5%
Black or African American	0.6%
Asian	0.0%
Hispanic or Latino (any race)	3.7%
Two or More Races	0.0%

Age & Sex

41.3

Median Age

50.3%

Female

49.7%

Male

19.9%

Age 65+

Age Distribution

Under 5

5.4%

5–9

6.0%

10–14

6.3%

15–19

5.9%

20–24

5.3%

25–34

12.1%

35–44

13.2%

45–54

11.7%

55–59

7.0%

60–64

7.1%

65–74

12.6%

75–84

5.8%

85+

1.5%

Children (under 15): 17.7% · Seniors (65+): 19.9%

Income & Poverty

Median household income	$74,543+$4,621 vs state
Mean household income	$100,531
Per-capita income	$43,263
Poverty rate	4.4%-2.7% vs state
Unemployment rate	2.2%
Employment-to-population	60.8%

Top Industries by Employment

Professional & business services

25.4%

Public administration

15.9%

Education & health care

9.1%

Finance & real estate

9.0%

Construction

8.2%

Information

6.6%

Arts, entertainment & food

4.5%

Agriculture

3.0%

The largest employment sector in Lewis and Clark County is professional & business services, accounting for 25.4% of workers.

How residents commute

0.2%

Drive alone

4.8%

Carpool

69.2%

Public transit

12.9%

Work from home

17.5 min

Avg commute

Housing

$358,200+$20,100 vs state

Median home value

$1,062

Median rent

69.7%

Homeownership rate

33,837

Total housing units

90.6%

Occupied

9.4%

Vacant

30.3%

Renter-occupied

Social & access

93.8%

With health insurance

94.2%

With broadband internet

44.7%

Foreign-born

10.4%

Veterans (18+)

14.5%

With a disability

96.9%

Speak language other than English at home

Education

94.9%

High School+

42.8%

Bachelor's+

Largest cities in Montana

Billings (118,321)Missoula (75,600)Great Falls (60,412)Bozeman (55,042)Butte-Silver Bow (34,929)Helena (33,126)Kalispell (26,830)Belgrade (11,425)All Montana cities →

Other counties in Montana

Yellowstone County (167,340)Gallatin County (122,194)Missoula County (119,639)Flathead County (108,445)Cascade County (84,601)Ravalli County (45,807)Silver Bow County (35,589)Lake County (32,073)Lincoln County (20,656)Park County (17,484)All Montana counties →

Part of Montana

Montana demographic profile All Montana data →

Metro areas in Montana

Billings (187,269)Missoula (124,435)Bozeman (122,194)Helena (92,391)Great Falls (84,601)All US metros →

County rankings

US Counties by Population Richest US Counties by Median Household Income Expensive US Counties by Home Value Educated US Counties Counties With Highest Poverty Rates Youngest US Counties by Median Age Oldest US Counties by Median Age Cheapest US Counties by Median Home Value Racially Diverse US Counties Counties With Largest Hispanic Population All rankings →

Frequently Asked Questions

Lewis and Clark County, Montana has a population of 72,580 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 6th-largest county in Montana. Population density is 21 people per square mile.

The population of Lewis and Clark County has grown 18.2% since 2010 (63,578 → 75,129), a +1.20% annualized rate.

The median household income in Lewis and Clark County, Montana is $74,543, with mean (average) household income of $100,531 and per-capita income of $43,263. 4.4% of residents live below the federal poverty level.

In Lewis and Clark County, the largest racial and ethnic groups are White (91.5%), Hispanic or Latino (3.7%), Black or African American (0.6%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.

The median age in Lewis and Clark County, Montana is 41.3 years. Residents are 50.3% female and 49.7% male.

The median home value in Lewis and Clark County is $358,200 and median monthly rent is $1,062. 69.7% of occupied housing units are owner-occupied. The county has 33,837 total housing units, 9.4% of which are vacant.

The largest employment sector in Lewis and Clark County, Montana is professional, scientific, and management services, employing 25.4% of workers. The unemployment rate is 2.2%.

Billings is among the largest cities associated with Lewis and Clark County, Montana, with a population of 118,321.