Demographics of Monroe County, Illinois

Monroe County, Illinois had 34,840 people on July 1, 2025, by the Census Bureau’s estimate: −121 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.

Monroe County, in four figures

34,840
Population: July 1, 2025, Vintage 2025 estimate.; −0.3%
Change since July 2020: −121 people.; 43.2 ±0.5
Median age: ACS 2020–⁠2024.; $102,880 ±$5,432
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.

Monroe County, Illinois's population shrank 0.3% from July 2020 to July 2025, against +3.1% nationally

The July 1 estimate of Monroe 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

Monroe County, Illinois's population shrank 0.3% from July 2020 to July 2025, against +3.1% nationally. The July 1 estimate of Monroe 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	34,961	100.0	100.0
2021	35,031	100.2	100.2
2022	35,129	100.5	100.7
2023	35,190	100.7	101.6
2024	35,105	100.4	102.5
2025	34,840	99.7	103.1

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Population of Monroe 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	34,961	+5	0	0	+2
2021	35,031	+70	−63	+3	+94
2022	35,129	+98	−23	0	+148
2023	35,190	+61	−100	−1	+172
2024	35,105	−85	−122	−1	+40
2025	34,840	−265	−173	−7	−86

Age, 2020–2024

The median age is 43.2 ±0.5: for men 42.5 ±0.8 and for women 44.2 ±0.5. Shares are of everyone the survey counts, in the Bureau’s sex-by-age table (B01001).

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People in Monroe County by age, ACS 2020–2024
Age	People	Share	Illinois	United States
Under 5	1,807 ±59	5.2% ±0.2	5.4% ±<0.1	5.6% ±<0.1
5 to 17	5,844 ±345	16.7% ±1.0	16.4% ±0.1	16.3% ±<0.1
18 to 24	2,326 ±266	6.6% ±0.8	9.1% ±<0.1	9.1% ±<0.1
25 to 44	8,454 ±397	24.1% ±1.1	26.9% ±0.1	26.9% ±<0.1
45 to 64	9,692 ±433	27.7% ±1.2	25.2% ±0.1	24.8% ±<0.1
65 and over	6,913 ±476	19.7% ±1.4	17.0% ±0.1	17.2% ±<0.1

Income and poverty, 2020–2024

Median household income is $102,880 ±$5,432, and income per person $49,605 ±$1,904, 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 Monroe County by income, ACS 2020–2024
Household income	Households	Share	Illinois	United States
Under $25,000	1,488 ±299	10.7% ±2.1	14.6% ±0.1	14.6% ±<0.1
$25,000 to $49,999	1,610 ±317	11.6% ±2.3	16.0% ±0.2	16.7% ±<0.1
$50,000 to $74,999	1,892 ±279	13.7% ±2.0	14.8% ±0.1	15.5% ±<0.1
$75,000 to $99,999	1,704 ±307	12.3% ±2.2	12.6% ±0.1	12.6% ±<0.1
$100,000 to $149,999	3,041 ±372	22.0% ±2.7	18.0% ±0.2	17.5% ±<0.1
$150,000 to $199,999	1,802 ±261	13.0% ±1.9	10.1% ±0.1	9.6% ±<0.1
$200,000 or more	2,314 ±305	16.7% ±2.2	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 Monroe County by age, ACS 2020–2024
Age	Below poverty	Rate	Illinois	United States
All ages	1,739 ±372	5.0% ±1.1	11.8% ±0.1	12.5% ±0.1
Under 18	389 ±160	5.2% ±2.1	15.1% ±0.2	16.1% ±0.1
18 to 59	663 ±218	3.7% ±1.2	11.0% ±0.1	11.6% ±0.1
60 and over	687 ±179	7.3% ±1.9	10.6% ±0.1	11.0% ±<0.1

Housing, 2020–2024

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Housing in Monroe County, ACS 2020–2024
Measure	Monroe County	Illinois	United States
Housing units	14,759 ±32	5,457,452 ±471	143,775,355 ±10,234
Occupied	93.8% ±1.8	92.3% ±0.1	89.9% ±0.1
Vacant	6.2% ±1.9	7.7% ±0.1	10.1% ±0.1
Owner occupied	84.7% ±1.4	67.1% ±0.3	65.2% ±0.3
Renter occupied	15.3% ±1.6	32.9% ±0.2	34.8% ±0.1
Median home value	$282,100 ±$13,470	$263,300 ±$797	$332,700 ±$236
Median gross rent	$1,042 ±$61	$1,274 ±$5	$1,413 ±$2
Median year built	1990 ±2	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 Monroe County by Hispanic origin and race, ACS 2020–2024
Origin	People	Share	Illinois	United States
Hispanic or Latino	683 ±0	1.9% ±<0.1	18.8% ±<0.1	19.3% ±<0.1
White alone, not Hispanic	33,291 ±115	95.0% ±0.3	58.1% ±<0.1	57.4% ±<0.1
Black alone, not Hispanic	207 ±72	0.6% ±0.2	13.3% ±<0.1	11.9% ±<0.1
Asian alone, not Hispanic	209 ±63	0.6% ±0.2	5.9% ±<0.1	5.9% ±<0.1
American Indian and Alaska Native alone, not Hispanic	0 to 41	0% to 0.1%	0.1% ±<0.1	0.5% ±<0.1
Native Hawaiian and Other Pacific Islander alone, not Hispanic	0 to 27	0% to 0.1%	< 0.1% ±<0.1	0.2% ±<0.1
Some other race alone, not Hispanic	0 to 129	0% to 0.4%	0.4% ±<0.1	0.6% ±<0.1
Two or more races, not Hispanic	564 ±156	1.6% ±0.4	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 Monroe County by place of birth and citizenship, ACS 2020–2024
Born	People	Share	Illinois	United States
Born in the state	18,936 ±862	54.0% ±2.5	66.5% ±0.1	57.3% ±<0.1
Born in another state	15,445 ±873	44.1% ±2.5	17.5% ±0.1	26.9% ±<0.1
Born a citizen outside the states	110 to 346	0.3% to 1.0%	1.3% ±<0.1	1.7% ±<0.1
Born abroad	427 ±110	1.2% ±0.3	14.7% ±0.1	14.1% ±<0.1
Naturalized citizens	278 ±72	0.8% ±0.2	7.7% ±0.1	7.4% ±<0.1
Not citizens	57 to 241	0.2% to 0.7%	7.0% ±0.1	6.8% ±<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%.

Monroe County among the counties of Illinois

40th of 102 by population, July 2025. Every one is listed on the Illinois page.

Counties of Illinois near Monroe County in population, July 2025
County	July 2025	Change since 2020
Clinton County	37,128	+0.6%
Franklin County	36,916	−2.1%
Marion County	36,382	−3.4%
Jefferson County	36,147	−2.3%
Livingston County	35,057	−2.1%
Monroe County	34,840	−0.3%
Effingham County	34,519	−0.5%
Christian County	33,443	−1.5%
Lee County	32,914	−3.4%
Fulton County	32,901	−2.0%
Morgan County	32,515	−2.9%

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