Demographics of Jefferson County, Kansas

Jefferson County, Kansas had 18,296 people on July 1, 2025, by the Census Bureau’s estimate: −34 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

18,296
Population: July 1, 2025, Vintage 2025 estimate.; −0.2%
Change since July 2020: −34 people.; 44.2 ±0.3
Median age: ACS 2020–⁠2024.; $81,278 ±$4,961
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, Kansas's population shrank 0.2% from July 2020 to July 2025, against +3.1% nationally

The July 1 estimate of Jefferson County, Kansas'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, Kansas's population shrank 0.2% from July 2020 to July 2025, against +3.1% nationally. The July 1 estimate of Jefferson County, Kansas'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	18,330	100.0	100.0
2021	18,446	100.6	100.2
2022	18,350	100.1	100.7
2023	18,297	99.8	101.6
2024	18,307	99.9	102.5
2025	18,296	99.8	103.1

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Population of Jefferson County, Kansas on July 1 of each year, Vintage 2025
July 1	Population	Change	Births less deaths	From abroad	From elsewhere in the country
2020	18,330	−38	−3	0	−33
2021	18,446	+116	−38	+3	+140
2022	18,350	−96	−57	+2	−29
2023	18,297	−53	−61	+5	+6
2024	18,307	+10	−47	+5	+55
2025	18,296	−11	−49	0	+39

Age, 2020–2024

The median age is 44.2 ±0.3: for men 44.1 ±0.4 and for women 44.4 ±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	Kansas	United States
Under 5	941 ±51	5.1% ±0.3	6.0% ±<0.1	5.6% ±<0.1
5 to 17	3,092 ±224	16.9% ±1.2	17.8% ±0.1	16.3% ±<0.1
18 to 24	1,219 ±133	6.6% ±0.7	10.2% ±0.1	9.1% ±<0.1
25 to 44	4,212 ±204	23.0% ±1.1	25.8% ±0.1	26.9% ±<0.1
45 to 64	5,219 ±268	28.4% ±1.5	23.3% ±0.1	24.8% ±<0.1
65 and over	3,666 ±272	20.0% ±1.5	17.0% ±0.2	17.2% ±<0.1

Income and poverty, 2020–2024

Median household income is $81,278 ±$4,961, and income per person $41,568 ±$2,186, in 2024 dollars. The median is $74,275 ±$475 in Kansas 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	Kansas	United States
Under $25,000	732 ±170	9.9% ±2.3	13.9% ±0.3	14.6% ±<0.1
$25,000 to $49,999	1,261 ±215	17.0% ±2.9	18.9% ±0.3	16.7% ±<0.1
$50,000 to $74,999	1,222 ±176	16.5% ±2.3	17.7% ±0.3	15.5% ±<0.1
$75,000 to $99,999	1,196 ±202	16.1% ±2.7	13.5% ±0.3	12.6% ±<0.1
$100,000 to $149,999	1,583 ±207	21.4% ±2.7	17.7% ±0.3	17.5% ±<0.1
$150,000 to $199,999	753 ±145	10.2% ±1.9	8.8% ±0.2	9.6% ±<0.1
$200,000 or more	665 ±136	9.0% ±1.8	9.6% ±0.2	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	Kansas	United States
All ages	1,023 ±246	5.6% ±1.4	11.3% ±0.2	12.5% ±0.1
Under 18	139 ±64	3.5% ±1.6	13.1% ±0.4	16.1% ±0.1
18 to 59	532 ±187	5.9% ±2.1	11.5% ±0.2	11.6% ±0.1
60 and over	352 ±101	7.0% ±2.0	9.0% ±0.3	11.0% ±<0.1

Housing, 2020–2024

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Housing in Jefferson County, ACS 2020–2024
Measure	Jefferson County	Kansas	United States
Housing units	8,038 ±31	1,293,635 ±880	143,775,355 ±10,234
Occupied	92.2% ±2.2	90.8% ±0.3	89.9% ±0.1
Vacant	7.8% ±2.2	9.2% ±0.3	10.1% ±0.1
Owner occupied	85.7% ±2.6	67.2% ±0.4	65.2% ±0.3
Renter occupied	14.3% ±2.8	32.8% ±0.3	34.8% ±0.1
Median home value	$216,900 ±$9,772	$217,200 ±$1,343	$332,700 ±$236
Median gross rent	$835 ±$64	$1,060 ±$7	$1,413 ±$2
Median year built	1979 ±2	1976 ±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	Kansas	United States
Hispanic or Latino	648 ±0	3.5% ±<0.1	13.6% ±<0.1	19.3% ±<0.1
White alone, not Hispanic	16,710 ±105	91.1% ±0.6	72.7% ±0.1	57.4% ±<0.1
Black alone, not Hispanic	31 to 133	0.2% to 0.7%	5.2% ±0.1	11.9% ±<0.1
Asian alone, not Hispanic	18 to 72	0.1% to 0.4%	2.9% ±<0.1	5.9% ±<0.1
American Indian and Alaska Native alone, not Hispanic	79 ±33	0.4% ±0.2	0.4% ±<0.1	0.5% ±<0.1
Native Hawaiian and Other Pacific Islander alone, not Hispanic	0 to 9	0% to < 0.1%	0.1% ±<0.1	0.2% ±<0.1
Some other race alone, not Hispanic	3 to 95	< 0.1% to 0.5%	0.4% ±<0.1	0.6% ±<0.1
Two or more races, not Hispanic	733 ±125	4.0% ±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	Kansas	United States
Born in the state	13,983 ±476	76.2% ±2.6	59.2% ±0.3	57.3% ±<0.1
Born in another state	4,097 ±488	22.3% ±2.7	32.4% ±0.2	26.9% ±<0.1
Born a citizen outside the states	34 to 146	0.2% to 0.8%	1.1% ±<0.1	1.7% ±<0.1
Born abroad	179 ±64	1.0% ±0.3	7.4% ±0.1	14.1% ±<0.1
Naturalized citizens	42 to 132	0.2% to 0.7%	3.2% ±0.1	7.4% ±<0.1
Not citizens	41 to 143	0.2% to 0.8%	4.2% ±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%.

Jefferson County among the counties of Kansas

30th of 105 by population, July 2025. Every one is listed on the Kansas page.

Counties of Kansas near Jefferson County in population, July 2025
County	July 2025	Change since 2020
Sumner County	22,312	−0.1%
Seward County	21,073	−3.6%
Labette County	19,685	−2.4%
Cherokee County	19,105	−1.0%
Dickinson County	18,637	+1.4%
Jefferson County	18,296	−0.2%
Atchison County	16,172	−0.9%
Osage County	15,693	−0.3%
Neosho County	15,637	−1.8%
Bourbon County	14,319	−0.1%
Jackson County	13,438	+1.5%

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