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 distinguished by its share of foreign-born residents, 10.9% of the population. With 12,826 residents, Cass County is a county in Illinois.
The typical household here earns about $64,907, below the US median of $78,538. About 8.6% of residents live below the federal poverty level, below the national 12.4%. Real estate is inexpensive, with a typical home worth only $95,500, with typical rent around $723.
Degree attainment is mid-range for US counties: 20.0% of adults hold a four-year degree, below the national 35.0%. Just 5.8% of workers are home-based, below the national 14.0%, and the average commute runs about 22 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.