Demographics of Jefferson County, Missouri

Jefferson County, Missouri had 233,132 people on July 1, 2025, by the Census Bureau’s estimate: +6,188 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.

Jefferson County, in four figures

233,132
Population: July 1, 2025, Vintage 2025 estimate.; +2.7%
Change since July 2020: +6,188 people.; 40.3 ±0.3
Median age: ACS 2020–⁠2024.; $82,851 ±$2,327
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.

Jefferson County, Missouri's population grew 2.7% from July 2020 to July 2025, against +3.1% nationally

The July 1 estimate of Jefferson County, Missouri'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

Jefferson County, Missouri's population grew 2.7% from July 2020 to July 2025, against +3.1% nationally. The July 1 estimate of Jefferson County, Missouri'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	226,944	100.0	100.0
2021	228,062	100.5	100.2
2022	229,270	101.0	100.7
2023	231,207	101.9	101.6
2024	232,134	102.3	102.5
2025	233,132	102.7	103.1

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Population of Jefferson County, Missouri on July 1 of each year, Vintage 2025
July 1	Population	Change	Births less deaths	From abroad	From elsewhere in the country
2020	226,944	+371	+45	0	+260
2021	228,062	+1,118	−156	+27	+1,082
2022	229,270	+1,208	−262	+44	+1,518
2023	231,207	+1,937	−89	+83	+1,957
2024	232,134	+927	+42	+79	+817
2025	233,132	+998	−30	+16	+1,000

Age, 2020–2024

The median age is 40.3 ±0.3: for men 39.7 ±0.3 and for women 41.1 ±0.5. Shares are of everyone the survey counts, in the Bureau’s sex-by-age table (B01001).

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People in Jefferson County by age, ACS 2020–2024
Age	People	Share	Missouri	United States
Under 5	12,635 ±177	5.5% ±0.1	5.8% ±<0.1	5.6% ±<0.1
5 to 17	38,998 ±1,091	17.0% ±0.5	16.6% ±0.1	16.3% ±<0.1
18 to 24	17,013 ±736	7.4% ±0.3	9.1% ±0.1	9.1% ±<0.1
25 to 44	59,970 ±1,065	26.1% ±0.5	26.0% ±0.1	26.9% ±<0.1
45 to 64	62,581 ±1,418	27.3% ±0.6	24.6% ±0.1	24.8% ±<0.1
65 and over	38,261 ±1,216	16.7% ±0.5	17.9% ±0.1	17.2% ±<0.1

Income and poverty, 2020–2024

Median household income is $82,851 ±$2,327, and income per person $39,160 ±$821, in 2024 dollars. The median is $70,702 ±$325 in Missouri and $80,734 ±$166 in the United States.

Households by income

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Households in Jefferson County by income, ACS 2020–2024
Household income	Households	Share	Missouri	United States
Under $25,000	9,773 ±847	11.1% ±1.0	15.8% ±0.2	14.6% ±<0.1
$25,000 to $49,999	15,169 ±1,100	17.2% ±1.2	19.6% ±0.2	16.7% ±<0.1
$50,000 to $74,999	15,071 ±995	17.1% ±1.1	17.4% ±0.2	15.5% ±<0.1
$75,000 to $99,999	13,156 ±920	14.9% ±1.0	13.2% ±0.2	12.6% ±<0.1
$100,000 to $149,999	19,097 ±1,193	21.6% ±1.3	17.1% ±0.2	17.5% ±<0.1
$150,000 to $199,999	8,952 ±639	10.1% ±0.7	8.2% ±0.1	9.6% ±<0.1
$200,000 or more	7,091 ±642	8.0% ±0.7	8.7% ±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 Jefferson County by age, ACS 2020–2024
Age	Below poverty	Rate	Missouri	United States
All ages	20,464 ±1,895	9.0% ±0.8	12.6% ±0.2	12.5% ±0.1
Under 18	5,844 ±747	11.6% ±1.4	15.8% ±0.4	16.1% ±0.1
18 to 59	9,638 ±995	7.9% ±0.8	12.0% ±0.2	11.6% ±0.1
60 and over	4,982 ±720	9.1% ±1.3	10.9% ±0.2	11.0% ±<0.1

Housing, 2020–2024

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Housing in Jefferson County, ACS 2020–2024
Measure	Jefferson County	Missouri	United States
Housing units	93,955 ±84	2,825,287 ±1,043	143,775,355 ±10,234
Occupied	94.0% ±0.7	88.8% ±0.2	89.9% ±0.1
Vacant	6.0% ±0.7	11.2% ±0.2	10.1% ±0.1
Owner occupied	82.2% ±1.0	68.1% ±0.3	65.2% ±0.3
Renter occupied	17.8% ±1.2	31.9% ±0.2	34.8% ±0.1
Median home value	$237,200 ±$3,773	$230,300 ±$880	$332,700 ±$236
Median gross rent	$979 ±$20	$1,033 ±$6	$1,413 ±$2
Median year built	1987 ±1	1978 ±1	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 Jefferson County by Hispanic origin and race, ACS 2020–2024
Origin	People	Share	Missouri	United States
Hispanic or Latino	6,066 ±0	2.6% ±<0.1	5.2% ±<0.1	19.3% ±<0.1
White alone, not Hispanic	202,967 ±1,675	88.5% ±0.7	76.3% ±0.1	57.4% ±<0.1
Black alone, not Hispanic	2,315 ±454	1.0% ±0.2	10.9% ±0.1	11.9% ±<0.1
Asian alone, not Hispanic	2,305 ±209	1.0% ±0.1	2.1% ±<0.1	5.9% ±<0.1
American Indian and Alaska Native alone, not Hispanic	197 ±84	0.1% ±<0.1	0.2% ±<0.1	0.5% ±<0.1
Native Hawaiian and Other Pacific Islander alone, not Hispanic	8 to 86	< 0.1%	0.1% ±<0.1	0.2% ±<0.1
Some other race alone, not Hispanic	760 ±259	0.3% ±0.1	0.4% ±<0.1	0.6% ±<0.1
Two or more races, not Hispanic	14,801 ±1,710	6.5% ±0.7	4.8% ±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 Jefferson County by place of birth and citizenship, ACS 2020–2024
Born	People	Share	Missouri	United States
Born in the state	182,818 ±1,717	79.7% ±0.7	65.6% ±0.2	57.3% ±<0.1
Born in another state	40,251 ±1,706	17.5% ±0.7	29.1% ±0.1	26.9% ±<0.1
Born a citizen outside the states	1,124 ±293	0.5% ±0.1	0.8% ±<0.1	1.7% ±<0.1
Born abroad	5,265 ±663	2.3% ±0.3	4.5% ±0.1	14.1% ±<0.1
Naturalized citizens	3,895 ±539	1.7% ±0.2	2.3% ±0.1	7.4% ±<0.1
Not citizens	1,370 ±367	0.6% ±0.2	2.2% ±0.1	6.8% ±<0.1

Jefferson County among the counties of Missouri

7th of 115 by population, July 2025. Every one is listed on the Missouri page.

Counties of Missouri near Jefferson County in population, July 2025
County	July 2025	Change since 2020
Jackson County	732,994	+2.1%
St. Charles County	426,499	+4.9%
Greene County	309,286	+3.3%
St. Louis city	278,144	−7.4%
Clay County	265,032	+4.3%
Jefferson County	233,132	+2.7%
Boone County	191,746	+4.2%
Jasper County	127,428	+3.7%
Cass County	115,859	+7.1%
Platte County	114,400	+6.7%
Franklin County	108,090	+3.1%

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