Demographics of Cass County, Illinois

Cass County, Illinois had 12,463 people on July 1, 2025, by the Census Bureau’s estimate: −515 since July 2020. Age, income, poverty, housing and origin below come from the American Community Survey, averaged over 2020–2024, each with its margin of error.

Cass County, in four figures

12,463
Population: July 1, 2025, Vintage 2025 estimate.; −4.0%
Change since July 2020: −515 people.; 38.3 ±0.9
Median age: ACS 2020–⁠2024.; $68,125 ±$4,852
Median household income: ACS 2020–⁠2024, in 2024 dollars.

Population, year by year

July 1 estimates from the Census Bureau’s Vintage 2025. Each year's change is births less deaths, net moves from abroad and net moves from elsewhere in the country, with the Bureau's small residual. The 2020 row's components run 3 months, from the April census to July 1.

Cass County, Illinois's population shrank 4.0% from July 2020 to July 2025, against +3.1% nationally

The July 1 estimate of Cass County, Illinois's resident population and the nation's, each year of the Census Bureau's Vintage 2025, as a share of its July 2020 level (= 100).

U.S. Census Bureau — Census Bureau population estimates — counties and Puerto Rico municipios, with components of change

About this chart

The figures

Cass County, Illinois's population shrank 4.0% from July 2020 to July 2025, against +3.1% nationally. The July 1 estimate of Cass County, Illinois's resident population and the nation's, each year of the Census Bureau's Vintage 2025, as a share of its July 2020 level (= 100).
July 1	Population	Index	United States
2020	12,978	100.0	100.0
2021	12,782	98.5	100.2
2022	12,657	97.5	100.7
2023	12,716	98.0	101.6
2024	12,530	96.5	102.5
2025	12,463	96.0	103.1

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Population of Cass County, Illinois on July 1 of each year, Vintage 2025
July 1	Population	Change	Births less deaths	From abroad	From elsewhere in the country
2020	12,978	−59	+8	0	−61
2021	12,782	−196	−7	+26	−206
2022	12,657	−125	+27	+83	−241
2023	12,716	+59	+24	+168	−134
2024	12,530	−186	−16	+169	−342
2025	12,463	−67	−19	+98	−146

Age, 2020–2024

The median age is 38.3 ±0.9: for men 38.2 ±1.1 and for women 38.5 ±1.4. Shares are of everyone the survey counts, in the Bureau’s sex-by-age table (B01001).

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People in Cass County by age, ACS 2020–2024
Age	People	Share	Illinois	United States
Under 5	856 ±64	6.7% ±0.5	5.4% ±<0.1	5.6% ±<0.1
5 to 17	2,263 ±174	17.7% ±1.4	16.4% ±0.1	16.3% ±<0.1
18 to 24	1,008 ±155	7.9% ±1.2	9.1% ±<0.1	9.1% ±<0.1
25 to 44	3,274 ±255	25.6% ±2.0	26.9% ±0.1	26.9% ±<0.1
45 to 64	3,076 ±199	24.1% ±1.6	25.2% ±0.1	24.8% ±<0.1
65 and over	2,307 ±210	18.0% ±1.6	17.0% ±0.1	17.2% ±<0.1

Income and poverty, 2020–2024

Median household income is $68,125 ±$4,852, and income per person $32,954 ±$2,227, in 2024 dollars. The median is $83,390 ±$362 in Illinois and $80,734 ±$166 in the United States.

Households by income

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Households in Cass County by income, ACS 2020–2024
Household income	Households	Share	Illinois	United States
Under $25,000	878 ±178	17.1% ±3.4	14.6% ±0.1	14.6% ±<0.1
$25,000 to $49,999	997 ±180	19.4% ±3.5	16.0% ±0.2	16.7% ±<0.1
$50,000 to $74,999	1,014 ±157	19.8% ±3.0	14.8% ±0.1	15.5% ±<0.1
$75,000 to $99,999	828 ±134	16.1% ±2.6	12.6% ±0.1	12.6% ±<0.1
$100,000 to $149,999	775 ±149	15.1% ±2.9	18.0% ±0.2	17.5% ±<0.1
$150,000 to $199,999	398 ±112	7.8% ±2.2	10.1% ±0.1	9.6% ±<0.1
$200,000 or more	238 ±72	4.6% ±1.4	13.8% ±0.1	13.4% ±0.1

Poverty by age

The poverty rate is the share of people whose family income is below the federal threshold for their family’s size, of everyone for whom the Bureau determines it (B17020).

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Poverty rate in Cass County by age, ACS 2020–2024
Age	Below poverty	Rate	Illinois	United States
All ages	1,406 ±286	11.1% ±2.3	11.8% ±0.1	12.5% ±0.1
Under 18	359 ±117	11.5% ±3.6	15.1% ±0.2	16.1% ±0.1
18 to 59	689 ±185	10.4% ±2.8	11.0% ±0.1	11.6% ±0.1
60 and over	358 ±111	12.2% ±3.7	10.6% ±0.1	11.0% ±<0.1

Housing, 2020–2024

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Housing in Cass County, ACS 2020–2024
Measure	Cass County	Illinois	United States
Housing units	5,676 ±27	5,457,452 ±471	143,775,355 ±10,234
Occupied	90.3% ±2.6	92.3% ±0.1	89.9% ±0.1
Vacant	9.7% ±2.6	7.7% ±0.1	10.1% ±0.1
Owner occupied	75.9% ±2.7	67.1% ±0.3	65.2% ±0.3
Renter occupied	24.1% ±3.2	32.9% ±0.2	34.8% ±0.1
Median home value	$97,100 ±$4,542	$263,300 ±$797	$332,700 ±$236
Median gross rent	$723 ±$88	$1,274 ±$5	$1,413 ±$2
Median year built	1968 ±5	1971 ±2	1980 ±1

Occupied and vacant are shares of all housing units; owner and renter occupied are shares of occupied units. Value and rent are medians in 2024 dollars.

Origin and place of birth, 2020–2024

Hispanic or Latino origin is not a race in the Census Bureau’s tables. Here the people of Hispanic origin, of any race, are one row, and everyone else is counted by race alone (B03002), so the rows add to the whole.

Hispanic origin and race

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People in Cass County by Hispanic origin and race, ACS 2020–2024
Origin	People	Share	Illinois	United States
Hispanic or Latino	2,929 ±0	22.9% ±<0.1	18.8% ±<0.1	19.3% ±<0.1
White alone, not Hispanic	8,934 ±45	69.9% ±0.4	58.1% ±<0.1	57.4% ±<0.1
Black alone, not Hispanic	508 ±118	4.0% ±0.9	13.3% ±<0.1	11.9% ±<0.1
Asian alone, not Hispanic	117 ±20	0.9% ±0.2	5.9% ±<0.1	5.9% ±<0.1
American Indian and Alaska Native alone, not Hispanic	0 to 18	0% to 0.1%	0.1% ±<0.1	0.5% ±<0.1
Native Hawaiian and Other Pacific Islander alone, not Hispanic	0 to 181	0% to 1.4%	< 0.1% ±<0.1	0.2% ±<0.1
Some other race alone, not Hispanic	7 to 99	0.1% to 0.8%	0.4% ±<0.1	0.6% ±<0.1
Two or more races, not Hispanic	164 ±63	1.3% ±0.5	3.4% ±0.1	4.3% ±<0.1

A range (the estimate less and plus its margin) where the Bureau's estimate is too uncertain to state as one number: a coefficient of variation over 30%.

Place of birth and citizenship

“Born a citizen outside the states” counts people born in Puerto Rico, the island areas, or abroad to American parents. Naturalized citizens and those who are not citizens together make up the people born abroad (B05002).

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People in Cass County by place of birth and citizenship, ACS 2020–2024
Born	People	Share	Illinois	United States
Born in the state	9,397 ±249	73.5% ±1.9	66.5% ±0.1	57.3% ±<0.1
Born in another state	1,345 ±242	10.5% ±1.9	17.5% ±0.1	26.9% ±<0.1
Born a citizen outside the states	229 ±86	1.8% ±0.7	1.3% ±<0.1	1.7% ±<0.1
Born abroad	1,813 ±208	14.2% ±1.6	14.7% ±0.1	14.1% ±<0.1
Naturalized citizens	400 ±118	3.1% ±0.9	7.7% ±0.1	7.4% ±<0.1
Not citizens	1,413 ±214	11.1% ±1.7	7.0% ±0.1	6.8% ±<0.1

Cass County among the counties of Illinois

81st of 102 by population, July 2025. Every one is listed on the Illinois page.

Counties of Illinois near Cass County in population, July 2025
County	July 2025	Change since 2020
Massac County	13,502	−4.5%
Johnson County	13,363	+0.3%
White County	13,250	−4.0%
Ford County	13,216	−2.2%
Clay County	12,793	−3.6%
Cass County	12,463	−4.0%
Mason County	12,411	−4.9%
Menard County	11,863	−3.3%
Marshall County	11,473	−2.0%
Greene County	11,313	−5.1%
Wabash County	10,907	−3.6%

Elsewhere on the site

Sources

Census Bureau population estimates — counties and Puerto Rico municipios, with components of change — U.S. Census Bureau · U.S. Government work · retrieved September 25, 2026
American Community Survey 5-year estimates — table-based Summary File · U.S. Government work

Data retrieved September 25, 2026