Jefferson County, Illinois Demographics 2026
Jefferson County, Illinois has a population of 36,550, the 38th most populous county in Illinois. The median household income is $63,118 and the median home value is $126,000. The poverty rate is 13.5%.
Data vintage: U.S. Census Bureau ACS 2020–2024 5-Year Estimates · refreshed July 2026 · Methodology & source notes
Jefferson County Quick Facts
How Jefferson County Changed
Change from the 2019–2023 ACS period to 2020–2024. These are rolling five-year estimates, not year-over-year measurements.
| Metric | 2019–2023 | 2020–2024 | Change |
|---|---|---|---|
| Population | 36,808 | 36,550 | -0.7% |
| Median household income | $61,102 | $63,118 | +3.3% |
| Median home value | $118,400 | $126,000 | +6.4% |
Median Household Income
Median Home Value
Economy & Housing
Household Income Distribution
Detailed income brackets
Employment
Housing Overview
People & Demographics
Age Distribution
Race & Ethnicity
Diversity Index
A less diverse community where one racial or ethnic group represents a large majority.
State average: 61 | National average: 61
Education
Educational Attainment (Adults 25+)
Cities & Places in Jefferson County
| City | Population | Median Income | Poverty | Home Value |
|---|---|---|---|---|
| Mount Vernon | 14,090 | $55,357 | 17.3% | $99,800 |
| Ina | 1,560 | $54,000 | 19.7% | $104,200 |
| Woodlawn | 632 | $72,500 | 10.2% | $132,700 |
| Dix | 568 | $46,339 | 10.7% | $100,000 |
| Bluford | 483 | $51,583 | 13.9% | $94,500 |
| Bonnie | 461 | $60,536 | 12.2% | $73,200 |
| Belle Rive | 382 | $53,281 | 8.4% | $94,600 |
| Waltonville | 294 | $63,750 | 15.0% | $111,400 |
| Opdyke | 246 | $63,750 | 2.5% | $67,800 |
| Nason | 203 | $50,052 | 29.7% | $73,600 |
Explore Illinois Rankings
Population Overview
Jefferson County is located in Illinois with a total population of 36,550. It is the 38th most populous county out of 102 in Illinois. The county encompasses 10 Census-designated places.
Age Demographics
The median age in Jefferson County is 41.2 years. This is 6% higher than the state median of 39.0 years.
Economy, Income & Housing
The median household income in Jefferson County is $63,118. This is 24% lower than the state median of $83,390. It is also 22% lower than the national median of $80,734. The poverty rate stands at 13.5%. This is 15% higher than the state poverty rate of 11.8%. The unemployment rate is 5.8%. This is 1% lower than the state rate of 5.8%. The median home value is $126,000. Housing costs are 52% lower than the state median of $263,300. With a home-value-to-income ratio of just 2.0x, Jefferson County is one of the most affordable housing markets in the area. 71.7% of occupied housing units are owner-occupied. This homeownership rate is 7% higher than the state average of 67.1%.
Race & Ethnicity
The largest racial or ethnic group in Jefferson County is White (non-Hispanic), making up 83.6% of the population. Black or African American residents account for 5.9%. The Black or African American population (5.9%) is well below the state average of 13.3%. The Hispanic or Latino population (2.8%) is well below the state average of 18.8%. The Asian population (1.0%) is well below the state average of 5.9%.
Education
18.2% of residents aged 25 and older hold a bachelor's degree or higher. This is 52% lower than the state rate of 37.9%. Nationally, 35.7% of adults hold at least a bachelor's degree. The high school graduation rate (or equivalent) is 92.3%.
Data Sources & Methodology
All figures for Jefferson County come from the U.S. Census Bureau's American Community Survey (ACS) 2020–2024 5-Year Estimates, with comparisons drawn against Illinois and national averages from the same dataset. See our methodology page for how each metric is defined, or data.census.gov for official tables with margins of error.
Frequently Asked Questions
What is the population of Jefferson County, Illinois?
Jefferson County has a population of 36,550, making it the 38th most populous county in Illinois.
What is the median income in Jefferson County?
The median household income in Jefferson County is $63,118 with a poverty rate of 13.5%.
How many cities are in Jefferson County, Illinois?
Jefferson County contains 10 Census-designated places.