Jefferson County, Illinois
Located in Illinois, Jefferson County has a population of 36,550 residents and a median age of 41.2 years, making it the #1,304 most populous county out of 3,222 nationwide. In terms of economic indicators, the county has a poverty rate of 13.5%. The median home value is $126,000, and the median household income is $63,118, which is 16% below the national median.
Demographics
Jefferson County has a population of 36,550, making it the #1,304 most populous county in the US. The median age is 41.2 years, which is 5.9% 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 $63,118, ranking #1,783 out of 3,222 counties — 16.0% below the national median. The poverty rate is 13.5% and unemployment stands at 5.8%.
Median Household Income Trend
Rankings →Income Distribution
Industry of Employment
Occupation
Housing
The median home value in Jefferson County is $126,000 (-55.3% vs national). Renters pay a median of $885/mo and the homeownership rate is 71.7%.
Median Home Value Trend
Rankings →Household Type
Education
In Jefferson County, 18.2% of adults age 25+ hold a bachelor's degree or higher, which is 46.1% below the national average, ranking #2,330 out of 3,222 counties.
Bachelor's Degree or Higher Trend
Rankings →Health & Wellbeing
Life expectancy in Jefferson County is 74.1 years. 18.8% of adults report poor or fair health and 6.0% lack health insurance. Data from County Health Rankings (2025).
Life Expectancy Trend
Substance Use
18.4% of adults in Jefferson County smoke , 38.8% are obese , and 21.3% report excessive drinking. The drug overdose death rate is 31.7 per 100,000.
Adult Smoking Trend
Safety
The homicide rate in Jefferson County is 3.8 per 100,000 and the suicide rate is 16.7 per 100,000. Motor vehicle deaths occur at a rate of 15.6 per 100,000.
Homicide Rate Trend
Families & Children
21.1% of children in Jefferson County live in poverty and the infant mortality rate is 9.3 per 1,000 live births. The teen birth rate is 29.8 per 1,000 females age 15–19.
Infant Mortality Trend
Civic & Transportation
Voter turnout in Jefferson County is 59.6%. The mean commute time is 21.8 min, which is 21.1% 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 47.8%. The vote was 25.5% Dem / 73.3% Rep. Compared to 2020, the margin shifted 2.6 toward Republicans .
Vote Share Over Time
About Jefferson County, Illinois
Jefferson County, Illinois has a total population of 36,550, making it the 1,304th most populous county in the United States. The median age in Jefferson County is 41.2 years, which is 5.9% above the national median of 38.9 years.
The median household income in Jefferson County is $63,118, which ranks #1,783 of 3,222 counties nationwide. This is 16.0% below the national median of $75,149. The poverty rate is 13.5%, higher than the national rate of 12.6%. The unemployment rate stands at 5.8%.
The median home value in Jefferson County is $126,000, 55.3% below the national median. Renters in Jefferson County pay a median gross rent of $885 per month. The homeownership rate is 71.7%, compared to the national rate of 64.4%.
In Jefferson County, 18.2% of residents aged 25 and older hold a bachelor's degree or higher, 46.1% below the national average of 33.7%. Health insurance coverage stands at 92.8% of the population. The average commute time for workers is 21.8 min.
Jefferson County is a diverse community. The largest racial or ethnic group is White (non-Hispanic) at 83.6% of the population, followed by Two or More Races (6.0%) and Black (non-Hispanic) (5.8%).
All data for Jefferson County, Illinois 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.