Jefferson County, Idaho
Located in Idaho, Jefferson County has a population of 33,154 residents and a median age of 32.8 years, making it the #1,390 most populous county out of 3,222 nationwide. In terms of economic indicators, the county has a poverty rate of 9.7%. The median home value is $408,400, and the median household income is $86,679, which is 15% above the national median.
Demographics
Jefferson County has a population of 33,154, making it the #1,390 most populous county in the US. The median age is 32.8 years, which is 15.7% below the national median.
Population Trend
Rankings →Year-over-Year Population Growth
Age & Sex Distribution
Race & Ethnicity
Nativity
Geographic Mobility (Past Year)
Economy
The median household income in Jefferson County is $86,679, ranking #384 out of 3,222 counties — 15.3% above the national median. The poverty rate is 9.7% and unemployment stands at 2.7%.
Median Household Income Trend
Rankings →Income Distribution
Industry of Employment
Occupation
Housing
The median home value in Jefferson County is $408,400 (+44.9% vs national). Renters pay a median of $1,138/mo and the homeownership rate is 83.0%.
Median Home Value Trend
Rankings →Household Type
Education
In Jefferson County, 27.4% of adults age 25+ hold a bachelor's degree or higher, which is 18.8% below the national average, ranking #973 out of 3,222 counties.
Bachelor's Degree or Higher Trend
Rankings →Health & Wellbeing
Life expectancy in Jefferson County is 77.4 years. 17.0% of adults report poor or fair health and 9.2% lack health insurance. Data from County Health Rankings (2025).
Life Expectancy Trend
Substance Use
15.5% of adults in Jefferson County smoke , 37.2% are obese , and 18.1% report excessive drinking.
Adult Smoking Trend
Safety
The suicide rate is 23.2 per 100,000. Motor vehicle deaths occur at a rate of 17.0 per 100,000.
Suicide Rate Trend
Families & Children
8.9% of children in Jefferson County live in poverty . The teen birth rate is 13.1 per 1,000 females age 15–19.
Teen Birth Rate Trend
Civic & Transportation
Voter turnout in Jefferson County is 75.7%. The mean commute time is 27.5 min, which is 0.3% below the national average.
Voter Turnout Trend
Mean Commute Time Trend
Rankings →Elections
In the 2024 presidential election, Jefferson County voted Republican with a margin of 73.2%. The vote was 12% Dem / 85.2% Rep. Compared to 2020, the margin shifted +0.5 toward Democrats .
Vote Share Over Time
About Jefferson County, Idaho
Jefferson County, Idaho has a total population of 33,154, making it the 1,390th most populous county in the United States. The median age in Jefferson County is 32.8 years, which is 15.7% below the national median of 38.9 years.
The median household income in Jefferson County is $86,679, which ranks #384 of 3,222 counties nationwide. This is 15.3% above the national median of $75,149. The poverty rate is 9.7%, lower than the national rate of 12.6%. The unemployment rate stands at 2.7%.
The median home value in Jefferson County is $408,400, 44.9% above the national median. Renters in Jefferson County pay a median gross rent of $1,138 per month. The homeownership rate is 83.0%, compared to the national rate of 64.4%.
In Jefferson County, 27.4% of residents aged 25 and older hold a bachelor's degree or higher, 18.8% below the national average of 33.7%. Health insurance coverage stands at 92.2% of the population. The average commute time for workers is 27.5 min.
Jefferson County is a diverse community. The largest racial or ethnic group is White (non-Hispanic) at 85.7% of the population, followed by Hispanic or Latino (11.0%) and Two or More Races (2.6%).
All data for Jefferson County, Idaho comes from the U.S. Census Bureau's American Community Survey (ACS) 5-Year Estimates. These figures are estimates based on survey sampling and are subject to margin of error. For the most detailed and up-to-date data, visit the Census Bureau's official data portal.