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.
12,501
Population
+1.11%
Annual growth
8
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
The poverty rate is what most separates Jefferson County from the typical county: 2.7% of residents live below the federal poverty line, against 12.4% nationally. With 12,501 residents, Jefferson County is a county in Montana. It ranks #16 among counties in Montana by population.
The typical household earns $76,576 a year, near the US median of $78,538. Hardship is rare relative to US counties: a poverty rate of just 2.7%, below the national 12.4%. Real estate commands a premium here — a median home value of $408,000, with typical rent around $886.
College attainment is above the local norm at 32.7%, below the national 35.0%. About 11.9% of workers primarily work from home, below the national 14.0%, and the average commute runs about 22 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 |
|---|---|
| 2010 | 11,406 |
| 2011 | 11,373 |
| 2012 | 11,319 |
| 2013 | 11,457 |
| 2014 | 11,505 |
| 2015 | 11,576 |
| 2016 | 11,774 |
| 2017 | 11,918 |
| 2018 | 12,084 |
| 2019 | 12,211 |
| 2020 | 12,142 |
| 2021 | 12,472 |
| 2022 | 12,864 |
| 2023 | 13,086 |
| 2024 | 13,304 |
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
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
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
Other counties in Montana
Part of Montana
Metro areas in Montana
County 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.
Jefferson County, MT Climate
Jefferson County, MT has an average annual temperature of 4.2°C (40°F) and receives about 374 mm of precipitation per year. The warmest month is July and the coldest is January. Figures are 1970–2000 climate normals.
4.2°C
Avg Temp
374
Precip (mm/yr)
Jul
Hottest Month
Jan
Coldest Month
| Month | Avg (°C/°F) | Precip |
|---|---|---|
| January | -6° / 20° | 20 mm |
| February | -4° / 25° | 14 mm |
| March | -1° / 30° | 22 mm |
| April | 3° / 37° | 29 mm |
| May | 8° / 46° | 59 mm |
| June | 12° / 54° | 61 mm |
| July | 16° / 61° | 37 mm |
| August | 16° / 60° | 38 mm |
| September | 10° / 51° | 37 mm |
| October | 5° / 41° | 21 mm |
| November | -2° / 29° | 18 mm |
| December | -6° / 21° | 18 mm |
1970–2000 normals from WorldClim 2.1 (~9 km grid). Precipitation can be less precise near mountains or coastlines, where rainfall varies sharply over short distances.
Best time to visit Jefferson County, MT
The most comfortable months to visit Jefferson County, MT are typically July, August and June, when temperatures are mildest and rainfall is relatively low. The hottest month is July (around 25°C high). The coldest is January (near -12°C low). June is usually the wettest month.
Where to stay near Jefferson County
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Data from the American Community Survey (ACS) 5-Year estimates.
Source: U.S. Census Bureau ACS, 2026.