Jefferson County, Idaho Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 12th-largest in Idaho
The population of Jefferson County, Idaho is 32,234 as of the 2023 American Community Survey, making it the 12th-largest county in Idaho. The median household income is $82,952, the median home value is $335,000, and the median age is 32.3.
The population of Jefferson County has grown 32.9% since 2010 (26,222 → 34,854), a +2.05% annualized rate.
32,234
Population
+2.05%
Annual growth
29
People / sq mi
$82,952
Median Income
$335,000
Median Home Value
Jefferson County covers 1,094 sq mi of land at 29.5 people per square mile.
About Jefferson County, ID
Jefferson County is a county in Idaho with a population of 32,234. It ranks #12 among counties in Idaho by population. The median age is 32.3, younger than the national median. The population is 51.3% male and 48.7% female.
The median household income in Jefferson County is $82,952, above the US median of $74,580. 7.4% of residents live below the federal poverty level. Home values sit at a median of $335,000, with monthly rent averaging $1,098. The homeownership rate of 82.4% is higher than the national rate of 64.8%.
Educational attainment in Jefferson County reflects 27.2% of adults 25 and older holding a bachelor's degree or higher, below the national average of 34.3%. Roughly 7.3% of workers primarily work from home, below the national work-from-home rate of 14.2%. The average commute is 24.8 minutes each way.
Jefferson County Population History (2010-2024)
The county of Jefferson County had a population of 26,222 in 2010 and 34,854 in 2024, a 32.9% growth over 14 years. The peak was 34,854 in 2024. Average annual growth rate: 2.06%.
34,854
Population (2024)
26,222
Population (2010)
34,854
Peak (2024)
2.06%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 26,222 |
| 2011 | 26,315 |
| 2012 | 26,642 |
| 2013 | 26,809 |
| 2014 | 26,948 |
| 2015 | 27,133 |
| 2016 | 27,827 |
| 2017 | 28,448 |
| 2018 | 29,418 |
| 2019 | 29,918 |
| 2020 | 31,082 |
| 2021 | 32,208 |
| 2022 | 33,365 |
| 2023 | 34,259 |
| 2024 | 34,854 |
Race & Ethnicity
| White | 88.3% |
| Black or African American | 0.1% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 2.4% |
| Two or More Races | 0.0% |
Age & Sex
32.3
Median Age
48.7%
Female
51.3%
Male
11.5%
Age 65+
Age Distribution
Children (under 15): 26.7% · Seniors (65+): 11.5%
Income & Poverty
| Median household income | $82,952+$8,316 vs state |
| Mean household income | $95,822 |
| Per-capita income | $30,733 |
| Poverty rate | 7.4%+0.4% vs state |
| Unemployment rate | 1.6% |
| Employment-to-population | 64.5% |
Top Industries by Employment
The largest employment sector in Jefferson County is professional & business services, accounting for 24.0% of workers.
How residents commute
2.4%
Drive alone
1.5%
Carpool
78.6%
Public transit
7.3%
Work from home
24.8 min
Avg commute
Housing
$335,000$-41,000 vs state
Median home value
$1,098
Median rent
82.4%
Homeownership rate
10,499
Total housing units
94.3%
Occupied
5.7%
Vacant
17.6%
Renter-occupied
Social & access
91.4%
With health insurance
97.2%
With broadband internet
28.3%
Foreign-born
5.6%
Veterans (18+)
10.8%
With a disability
88.9%
Speak language other than English at home
Education
93.3%
High School+
27.2%
Bachelor's+
Largest cities in Idaho
Other counties in Idaho
Part of Idaho
Metro areas in Idaho
County rankings
Frequently Asked Questions
Jefferson County, Idaho has a population of 32,234 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 12th-largest county in Idaho. Population density is 29 people per square mile.
The population of Jefferson County has grown 32.9% since 2010 (26,222 → 34,854), a +2.05% annualized rate.
The median household income in Jefferson County, Idaho is $82,952, with mean (average) household income of $95,822 and per-capita income of $30,733. 7.4% of residents live below the federal poverty level.
In Jefferson County, the largest racial and ethnic groups are White (88.3%), Hispanic or Latino (2.4%), 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, Idaho is 32.3 years. Residents are 48.7% female and 51.3% male.
The median home value in Jefferson County is $335,000 and median monthly rent is $1,098. 82.4% of occupied housing units are owner-occupied. The county has 10,499 total housing units, 5.7% of which are vacant.
The largest employment sector in Jefferson County, Idaho is professional, scientific, and management services, employing 24.0% of workers. The unemployment rate is 1.6%.
Boise City is among the largest cities associated with Jefferson County, Idaho, with a population of 235,701.
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Statewide data for Idaho
Population, race, income, age, and trends across Idaho
Data from the American Community Survey (ACS) 5-Year estimates.
Source: U.S. Census Bureau ACS, 2026.