Williamson County, Illinois
Located in Illinois, Williamson County has a population of 66,876 residents and a median age of 41.6 years, making it the #820 most populous county out of 3,222 nationwide. In terms of economic indicators, the county has a poverty rate of 13.8%. The median home value is $156,400, and the median household income is $65,604, which is 13% below the national median.
Demographics
Williamson County has a population of 66,876, making it the #820 most populous county in the US. The median age is 41.6 years, which is 6.9% 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 Williamson County is $65,604, ranking #1,582 out of 3,222 counties — 12.7% below the national median. The poverty rate is 13.8% and unemployment stands at 5.0%.
Median Household Income Trend
Rankings →Income Distribution
Industry of Employment
Occupation
Housing
The median home value in Williamson County is $156,400 (-44.5% vs national). Renters pay a median of $930/mo and the homeownership rate is 70.7%.
Median Home Value Trend
Rankings →Household Type
Education
In Williamson County, 26.2% of adults age 25+ hold a bachelor's degree or higher, which is 22.1% below the national average, ranking #1,077 out of 3,222 counties.
Bachelor's Degree or Higher Trend
Rankings →Health & Wellbeing
Life expectancy in Williamson County is 75.5 years. 18.0% of adults report poor or fair health and 5.0% lack health insurance. Data from County Health Rankings (2025).
Life Expectancy Trend
Substance Use
18.6% of adults in Williamson County smoke , 38.4% are obese , and 21.1% report excessive drinking. The drug overdose death rate is 24.5 per 100,000.
Adult Smoking Trend
Safety
The homicide rate in Williamson County is 3.0 per 100,000 and the suicide rate is 15.4 per 100,000. Motor vehicle deaths occur at a rate of 15.6 per 100,000.
Homicide Rate Trend
Families & Children
21.9% of children in Williamson County live in poverty and the infant mortality rate is 5.9 per 1,000 live births. The teen birth rate is 20.2 per 1,000 females age 15–19.
Infant Mortality Trend
Civic & Transportation
Voter turnout in Williamson County is 65.0%. The mean commute time is 25.3 min, which is 8.4% below the national average.
Voter Turnout Trend
Mean Commute Time Trend
Rankings →Elections
In the 2024 presidential election, Williamson County voted Republican with a margin of 38.7%. The vote was 30% Dem / 68.7% Rep. Compared to 2020, the margin shifted 1.4 toward Republicans .
Vote Share Over Time
About Williamson County, Illinois
Williamson County, Illinois has a total population of 66,876, making it the 820th most populous county in the United States. The median age in Williamson County is 41.6 years, which is 6.9% above the national median of 38.9 years.
The median household income in Williamson County is $65,604, which ranks #1,582 of 3,222 counties nationwide. This is 12.7% below the national median of $75,149. The poverty rate is 13.8%, higher than the national rate of 12.6%. The unemployment rate stands at 5.0%.
The median home value in Williamson County is $156,400, 44.5% below the national median. Renters in Williamson County pay a median gross rent of $930 per month. The homeownership rate is 70.7%, compared to the national rate of 64.4%.
In Williamson County, 26.2% of residents aged 25 and older hold a bachelor's degree or higher, 22.1% below the national average of 33.7%. Health insurance coverage stands at 95.4% of the population. The average commute time for workers is 25.3 min.
Williamson County is a diverse community. The largest racial or ethnic group is White (non-Hispanic) at 87.9% of the population, followed by Black (non-Hispanic) (4.3%) and Two or More Races (3.2%).
All data for Williamson 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.