Jefferson County, Montana Population 2026

Updated April 2026 · US Census ACS 2023 5-Year Estimates · 16th-largest in Montana

The population of Jefferson County, Montana is 12,501 as of the 2023 American Community Survey, making it the 16th-largest county in Montana. The median household income is $76,576, the median home value is $408,000, and the median age is 47.3.

The population of Jefferson County has grown 16.6% since 2010 (11,406 → 13,304), a +1.11% annualized rate.

Jefferson County within Montana · Source: US Census TIGER/Line via us-atlas

12,501

Population

+1.11%

Annual growth

People / sq mi

$76,576

Median Income

$408,000

Median Home Value

Jefferson County covers 1,657 sq mi of land at 7.5 people per square mile.

About Jefferson County, MT

Jefferson County is a county in Montana with a population of 12,501. It ranks #16 among counties in Montana by population. The median age is 47.3, older than the national median. The population is 50.7% male and 49.3% female.

The median household income in Jefferson County is $76,576, near the US median of $74,580. 2.7% of residents live below the federal poverty level. Home values sit at a median of $408,000, with monthly rent averaging $886. The homeownership rate of 83.1% is higher than the national rate of 64.8%.

Educational attainment in Jefferson County reflects 32.7% of adults 25 and older holding a bachelor's degree or higher, near the national average of 34.3%. Roughly 11.9% of workers primarily work from home, similar to the national work-from-home rate of 14.2%. The average commute is 22.3 minutes each way.

Jefferson County Population History (2010-2024)

The county of Jefferson County had a population of 11,406 in 2010 and 13,304 in 2024, a 16.6% growth over 14 years. The peak was 13,304 in 2024. Average annual growth rate: 1.11%.

13,304

Population (2024)

11,406

Population (2010)

13,304

Peak (2024)

1.11%

Avg Annual Growth

Year	Population	Change	Annual %	Source
2010	11,406	-	-	estimate
2011	11,373	-33	-0.29%	estimate
2012	11,319	-54	-0.47%	estimate
2013	11,457	+138	+1.22%	estimate
2014	11,505	+48	+0.42%	estimate
2015	11,576	+71	+0.62%	estimate
2016	11,774	+198	+1.71%	estimate
2017	11,918	+144	+1.22%	estimate
2018	12,084	+166	+1.39%	estimate
2019	12,211	+127	+1.05%	estimate
2020	12,142	-69	-0.57%	estimate
2021	12,472	+330	+2.72%	estimate
2022	12,864	+392	+3.14%	estimate
2023	13,086	+222	+1.73%	estimate
2024	13,304	+218	+1.67%	estimate

Race & Ethnicity

White	92.8%
Black or African American	0.1%
Asian	0.0%
Hispanic or Latino (any race)	3.9%
Two or More Races	0.0%

Age & Sex

47.3

Median Age

49.3%

Female

50.7%

Male

22.8%

Age 65+

Age Distribution

Under 5

4.4%

5–9

6.1%

10–14

5.4%

15–19

5.8%

20–24

4.9%

25–34

9.0%

35–44

11.9%

45–54

13.1%

55–59

8.2%

60–64

8.5%

65–74

15.8%

75–84

6.3%

85+

0.7%

Children (under 15): 15.9% · Seniors (65+): 22.8%

Income & Poverty

Median household income	$76,576+$6,654 vs state
Mean household income	$107,580
Per-capita income	$43,037
Poverty rate	2.7%-4.4% vs state
Unemployment rate	1.7%
Employment-to-population	56.6%

Top Industries by Employment

Professional & business services

19.8%

Public administration

13.5%

Construction

12.2%

Finance & real estate

11.4%

Arts, entertainment & food

6.4%

Agriculture

6.1%

Education & health care

5.6%

Retail trade

4.3%

The largest employment sector in Jefferson County is professional & business services, accounting for 19.8% of workers.

How residents commute

0.2%

Drive alone

3.0%

Carpool

72.2%

Public transit

11.9%

Work from home

22.3 min

Avg commute

Housing

$408,000+$69,900 vs state

Median home value

$886

Median rent

83.1%

Homeownership rate

5,388

Total housing units

90.8%

Occupied

9.2%

Vacant

16.9%

Renter-occupied

Social & access

94.9%

With health insurance

96.7%

With broadband internet

46.9%

Foreign-born

11.2%

Veterans (18+)

17.0%

With a disability

97.5%

Speak language other than English at home

Education

94.0%

High School+

32.7%

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)Lewis and Clark County (72,580)Ravalli County (45,807)Silver Bow County (35,589)Lake County (32,073)Lincoln County (20,656)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

Jefferson County, Montana has a population of 12,501 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 16th-largest county in Montana. Population density is 8 people per square mile.

The population of Jefferson County has grown 16.6% since 2010 (11,406 → 13,304), a +1.11% annualized rate.

The median household income in Jefferson County, Montana is $76,576, with mean (average) household income of $107,580 and per-capita income of $43,037. 2.7% of residents live below the federal poverty level.

In Jefferson County, the largest racial and ethnic groups are White (92.8%), Hispanic or Latino (3.9%), Black or African American (0.1%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.

The median age in Jefferson County, Montana is 47.3 years. Residents are 49.3% female and 50.7% male.

The median home value in Jefferson County is $408,000 and median monthly rent is $886. 83.1% of occupied housing units are owner-occupied. The county has 5,388 total housing units, 9.2% of which are vacant.

The largest employment sector in Jefferson County, Montana is professional, scientific, and management services, employing 19.8% of workers. The unemployment rate is 1.7%.

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