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Jefferson County, MT
10 cities and towns and 7 ZIP codes in Jefferson County, Montana.
Population
12,774
Land area
1,657sq mi
People per sq mi
8
ZIP codes
7
Cities and towns in Jefferson County
Jefferson County at a glance
- The median household income is $95,490, 32% above the Montana median of $72,509.
- A typical owner-occupied home is valued at $446,900 (19% above Montana) and median rent is $925 a month.
- Its largest cities are Montana City (3,092), Clancy (1,874) and Boulder (1,284).
Local data for Jefferson County, MT
Counts from official public data
Housing and community stats
Jefferson County, MT, American Community Survey 2020-2024
Median household income
$95,490
Poverty rate
5.7%
Median home value
$446,900
Prices +6.4% in a year
Median rent
$925/mo
Homeownership
84.2%
Bachelor's or higher
32.2%
Median age
47.1
Average commute
24.4 min
Largest reported origins and ancestries: German Americans (3,145), Irish Americans (2,428), Norwegian Americans (1,153).
Economy and federal money
Jobs, income, federal spending and pandemic loans
Unemployment rate
2.3%
Sep 2026, -0.6 pts in a year
Average annual pay
$57,412
2,784 jobs, 2025
Income per person
$68,296
BEA, 2024
Federal spending
$140M
FY 2026, $11,544 per person
PPP loans
$92.4M
1,450 loans, 12,840 jobs reported
Campaign donations
$339K
Itemized, 2026 cycle
How people get to work
Jefferson County, MT, workers 16 and older. American Community Survey 5-year estimates
- Drove alone74.6%
- Carpooled9.4%
- Public transit0.0%
- Walked2.2%
- Bicycle0.1%
- Taxi, ride-hailing, motorcycle or other1.0%
- Worked from home12.7%
Average one-way commute: 24.4 minutes for people who do not work from home.
Environment and hazard risk
Jefferson County, MT, from FEMA, NOAA and EPA
Natural hazard risk
Very Low
Top: landslide
Storm events since 1996
148
Most often hail
Flood insurance policies
22
0.3% of homes, county
July high / Jan low
83° / 12°F
10.8 inches of rain a year
Hazards, floods and storm historyCheck a flood zone5 historic places
Health statistics
Share of adults in Jefferson County, MT, CDC PLACES estimates
Obesity
32.8%
U.S. 33.3% -0.5 pts
Diabetes
10.3%
U.S. 12.1% -1.8 pts
Smoking
12.7%
U.S. 12.8% about the same
Uninsured (18-64)
8.1%
U.S. 11.1% -3.0 pts
Cities, towns and ZIP codes in Jefferson County
Population shown
Frequently asked questions
- What is the largest city in Jefferson County, MT?
- Montana City is the largest city or town in Jefferson County, with about 3,092 residents.
- How many ZIP codes are in Jefferson County?
- Jefferson County includes 7 ZIP Code Tabulation Areas, including 59631, 59632, 59634, 59635, 59638.
- What is the population of Jefferson County, MT?
- About 12,774 people live in Jefferson County, based on American Community Survey 5-year estimates.
- What counties border Jefferson County?
- Jefferson County borders Gallatin County, Lewis and Clark County, Silver Bow County, Deer Lodge County, Madison County, Broadwater County, Powell County.
Source: U.S. Census Bureau (TIGER/Line boundaries, American Community Survey) · Data as of 12/31/2023