Jefferson County, Missouri
Located in Missouri, Jefferson County has a population of 229,458 residents and a median age of 40.3 years, making it the #311 most populous county out of 3,222 nationwide. In terms of economic indicators, the county has a poverty rate of 9.0%. The median home value is $237,200, and the median household income is $82,851, which is 10% above the national median.
Demographics
Jefferson County has a population of 229,458, making it the #311 most populous county in the US. The median age is 40.3 years, which is 3.6% above 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 $82,851, ranking #489 out of 3,222 counties — 10.2% above the national median. The poverty rate is 9.0% and unemployment stands at 3.2%.
Median Household Income Trend
Rankings →Income Distribution
Industry of Employment
Occupation
Housing
The median home value in Jefferson County is $237,200 (-15.9% vs national). Renters pay a median of $979/mo and the homeownership rate is 82.2%.
Median Home Value Trend
Rankings →Household Type
Education
In Jefferson County, 24.7% of adults age 25+ hold a bachelor's degree or higher, which is 26.7% below the national average, ranking #1,267 out of 3,222 counties.
Bachelor's Degree or Higher Trend
Rankings →Health & Wellbeing
Life expectancy in Jefferson County is 75.0 years. 17.6% of adults report poor or fair health and 9.5% lack health insurance. Data from County Health Rankings (2025).
Life Expectancy Trend
Substance Use
19.8% of adults in Jefferson County smoke , 39.1% are obese , and 24.7% report excessive drinking. The drug overdose death rate is 49.7 per 100,000.
Adult Smoking Trend
Safety
The homicide rate in Jefferson County is 4.5 per 100,000 and the suicide rate is 25.1 per 100,000. Motor vehicle deaths occur at a rate of 18.1 per 100,000.
Homicide Rate Trend
Families & Children
10.9% of children in Jefferson County live in poverty and the infant mortality rate is 5.0 per 1,000 live births. The teen birth rate is 14.0 per 1,000 females age 15–19.
Infant Mortality Trend
Civic & Transportation
Voter turnout in Jefferson County is 68.1%. The mean commute time is 33.8 min, which is 22.4% above 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 36.7%. The vote was 31% Dem / 67.7% Rep. Compared to 2020, the margin shifted 2.9 toward Republicans .
Vote Share Over Time
About Jefferson County, Missouri
Jefferson County, Missouri has a total population of 229,458, making it the 311th most populous county in the United States. The median age in Jefferson County is 40.3 years, which is 3.6% above the national median of 38.9 years.
The median household income in Jefferson County is $82,851, which ranks #489 of 3,222 counties nationwide. This is 10.2% above the national median of $75,149. The poverty rate is 9.0%, lower than the national rate of 12.6%. The unemployment rate stands at 3.2%.
The median home value in Jefferson County is $237,200, 15.9% below the national median. Renters in Jefferson County pay a median gross rent of $979 per month. The homeownership rate is 82.2%, compared to the national rate of 64.4%.
In Jefferson County, 24.7% of residents aged 25 and older hold a bachelor's degree or higher, 26.7% below the national average of 33.7%. Health insurance coverage stands at 93.4% of the population. The average commute time for workers is 33.8 min.
Jefferson County is a diverse community. The largest racial or ethnic group is White (non-Hispanic) at 88.5% of the population, followed by Two or More Races (6.5%) and Hispanic or Latino (2.6%).
All data for Jefferson County, Missouri 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.