Cass County, Illinois Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 82nd-largest in Illinois
The population of Cass County, Illinois is 12,826 as of the 2023 American Community Survey, making it the 82nd-largest county in Illinois. The median household income is $64,907, the median home value is $95,500, and the median age is 38.1.
The population of Cass County has declined 6.7% since 2010 (13,632 → 12,713), a -0.50% annualized rate.
12,826
Population
-0.50%
Annual growth
34
People / sq mi
$64,907
Median Income
$95,500
Median Home Value
Cass County covers 376 sq mi of land at 34.1 people per square mile.
About Cass County, IL
Cass County is a county in Illinois with a population of 12,826. It ranks #82 among counties in Illinois by population. The median age is 38.1, in line with the national median. The population is 48.9% male and 51.1% female.
The median household income in Cass County is $64,907, below the US median of $74,580. 8.6% of residents live below the federal poverty level. Home values sit at a median of $95,500, with monthly rent averaging $723. The homeownership rate of 74.9% is higher than the national rate of 64.8%.
Educational attainment in Cass County reflects 20.0% of adults 25 and older holding a bachelor's degree or higher, below the national average of 34.3%. Roughly 5.8% of workers primarily work from home, below the national work-from-home rate of 14.2%. The average commute is 22.1 minutes each way.
Cass County Population History (2010-2024)
The county of Cass County had a population of 13,632 in 2010 and 12,713 in 2024, a -6.7% growth over 14 years. The peak was 13,632 in 2010. Average annual growth rate: -0.47%.
12,713
Population (2024)
13,632
Population (2010)
13,632
Peak (2010)
-0.47%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 13,632 |
| 2011 | 13,625 |
| 2012 | 13,427 |
| 2013 | 13,293 |
| 2014 | 13,079 |
| 2015 | 12,843 |
| 2016 | 12,677 |
| 2017 | 12,525 |
| 2018 | 12,353 |
| 2019 | 12,141 |
| 2020 | 12,976 |
| 2021 | 12,778 |
| 2022 | 12,672 |
| 2023 | 12,779 |
| 2024 | 12,713 |
Race & Ethnicity
| White | 77.7% |
| Black or African American | 3.8% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 0.8% |
| Two or More Races | 0.6% |
Age & Sex
38.1
Median Age
51.1%
Female
48.9%
Male
18.5%
Age 65+
Age Distribution
Children (under 15): 20.3% · Seniors (65+): 18.5%
Income & Poverty
| Median household income | $64,907$-16,795 vs state |
| Mean household income | $78,834 |
| Per-capita income | $32,047 |
| Poverty rate | 8.6%+0.4% vs state |
| Unemployment rate | 2.9% |
| Employment-to-population | 56.3% |
Top Industries by Employment
The largest employment sector in Cass County is manufacturing, accounting for 21.8% of workers.
How residents commute
0.0%
Drive alone
1.2%
Carpool
79.4%
Public transit
5.8%
Work from home
22.1 min
Avg commute
Housing
$95,500$-155,000 vs state
Median home value
$723
Median rent
74.9%
Homeownership rate
5,665
Total housing units
90.6%
Occupied
9.4%
Vacant
25.1%
Renter-occupied
Social & access
92.7%
With health insurance
90.6%
With broadband internet
10.9%
Foreign-born
6.1%
Veterans (18+)
16.1%
With a disability
78.7%
Speak language other than English at home
Education
86.7%
High School+
20.0%
Bachelor's+
Largest cities in Illinois
Other counties in Illinois
Part of Illinois
Metro areas in Illinois
County rankings
Frequently Asked Questions
Cass County, Illinois has a population of 12,826 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 82nd-largest county in Illinois. Population density is 34 people per square mile.
The population of Cass County has declined 6.7% since 2010 (13,632 → 12,713), a -0.50% annualized rate.
The median household income in Cass County, Illinois is $64,907, with mean (average) household income of $78,834 and per-capita income of $32,047. 8.6% of residents live below the federal poverty level.
In Cass County, the largest racial and ethnic groups are White (77.7%), Black or African American (3.8%), Hispanic or Latino (0.8%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.
The median age in Cass County, Illinois is 38.1 years. Residents are 51.1% female and 48.9% male.
The median home value in Cass County is $95,500 and median monthly rent is $723. 74.9% of occupied housing units are owner-occupied. The county has 5,665 total housing units, 9.4% of which are vacant.
The largest employment sector in Cass County, Illinois is manufacturing, employing 21.8% of workers. The unemployment rate is 2.9%.
Chicago is among the largest cities associated with Cass County, Illinois, with a population of 2,707,648.
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Statewide data for Illinois
Population, race, income, age, and trends across Illinois
Data from the American Community Survey (ACS) 5-Year estimates.
Source: U.S. Census Bureau ACS, 2026.