Demographics of Jefferson County, Iowa

Jefferson County, Iowa had 15,291 people on July 1, 2025, by the Census Bureau’s estimate: −397 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

15,291
Population: July 1, 2025, Vintage 2025 estimate.; −2.5%
Change since July 2020: −397 people.; 43.7 ±0.6
Median age: ACS 2020–⁠2024.; $61,620 ±$10,446
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, Iowa's population shrank 2.5% from July 2020 to July 2025, against +3.1% nationally

The July 1 estimate of Jefferson County, Iowa'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, Iowa's population shrank 2.5% from July 2020 to July 2025, against +3.1% nationally. The July 1 estimate of Jefferson County, Iowa'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	15,688	100.0	100.0
2021	15,795	100.7	100.2
2022	15,580	99.3	100.7
2023	15,464	98.6	101.6
2024	15,405	98.2	102.5
2025	15,291	97.5	103.1

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Population of Jefferson County, Iowa on July 1 of each year, Vintage 2025
July 1	Population	Change	Births less deaths	From abroad	From elsewhere in the country
2020	15,688	+26	0	+5	+18
2021	15,795	+107	−48	+112	+29
2022	15,580	−215	−71	+130	−283
2023	15,464	−116	−54	+256	−321
2024	15,405	−59	−50	+227	−238
2025	15,291	−114	−52	+197	−256

Age, 2020–2024

The median age is 43.7 ±0.6: for men 41.1 ±2.2 and for women 47.3 ±2.8. 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	Iowa	United States
Under 5	725 ±75	4.6% ±0.5	5.9% ±<0.1	5.6% ±<0.1
5 to 17	1,967 ±248	12.5% ±1.6	17.0% ±0.1	16.3% ±<0.1
18 to 24	1,255 ±228	8.0% ±1.5	10.0% ±0.1	9.1% ±<0.1
25 to 44	4,116 ±336	26.2% ±2.1	25.1% ±0.1	26.9% ±<0.1
45 to 64	3,450 ±265	22.0% ±1.7	23.9% ±0.1	24.8% ±<0.1
65 and over	4,192 ±342	26.7% ±2.2	18.1% ±0.1	17.2% ±<0.1

Income and poverty, 2020–2024

Median household income is $61,620 ±$10,446, and income per person $36,823 ±$4,353, in 2024 dollars. The median is $75,059 ±$418 in Iowa 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	Iowa	United States
Under $25,000	1,411 ±257	20.3% ±3.6	13.9% ±0.2	14.6% ±<0.1
$25,000 to $49,999	1,505 ±248	21.6% ±3.5	18.5% ±0.3	16.7% ±<0.1
$50,000 to $74,999	1,213 ±232	17.4% ±3.3	17.5% ±0.3	15.5% ±<0.1
$75,000 to $99,999	894 ±212	12.9% ±3.0	14.0% ±0.3	12.6% ±<0.1
$100,000 to $149,999	1,229 ±214	17.7% ±3.0	18.7% ±0.3	17.5% ±<0.1
$150,000 to $199,999	310 ±107	4.5% ±1.5	8.8% ±0.2	9.6% ±<0.1
$200,000 or more	390 ±129	5.6% ±1.8	8.6% ±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	Iowa	United States
All ages	2,225 ±517	15.2% ±3.5	11.1% ±0.2	12.5% ±0.1
Under 18	159 to 525	6.1% to 19.4%	12.9% ±0.3	16.1% ±0.1
18 to 59	1,402 ±382	20.9% ±5.5	11.4% ±0.3	11.6% ±0.1
60 and over	481 ±154	9.2% ±2.9	8.8% ±0.2	11.0% ±<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%.

Housing, 2020–2024

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Housing in Jefferson County, ACS 2020–2024
Measure	Jefferson County	Iowa	United States
Housing units	7,706 ±46	1,437,699 ±523	143,775,355 ±10,234
Occupied	90.2% ±2.9	91.5% ±0.3	89.9% ±0.1
Vacant	9.8% ±2.8	8.5% ±0.3	10.1% ±0.1
Owner occupied	67.7% ±3.4	71.7% ±0.3	65.2% ±0.3
Renter occupied	32.3% ±4.2	28.3% ±0.3	34.8% ±0.1
Median home value	$163,400 ±$8,367	$208,000 ±$1,141	$332,700 ±$236
Median gross rent	$883 ±$67	$972 ±$6	$1,413 ±$2
Median year built	1966 ±5	1972 ±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	Iowa	United States
Hispanic or Latino	644 ±0	4.1% ±<0.1	7.3% ±<0.1	19.3% ±<0.1
White alone, not Hispanic	12,941 ±97	82.4% ±0.6	82.3% ±0.1	57.4% ±<0.1
Black alone, not Hispanic	377 ±47	2.4% ±0.3	3.8% ±0.1	11.9% ±<0.1
Asian alone, not Hispanic	1,285 ±65	8.2% ±0.4	2.5% ±<0.1	5.9% ±<0.1
American Indian and Alaska Native alone, not Hispanic	0 to 27	0% to 0.2%	0.2% ±<0.1	0.5% ±<0.1
Native Hawaiian and Other Pacific Islander alone, not Hispanic	0 to 16	0% to 0.1%	0.2% ±<0.1	0.2% ±<0.1
Some other race alone, not Hispanic	0 to 108	0% to 0.7%	0.3% ±<0.1	0.6% ±<0.1
Two or more races, not Hispanic	395 ±103	2.5% ±0.7	3.5% ±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	Iowa	United States
Born in the state	8,639 ±431	55.0% ±2.7	69.6% ±0.2	57.3% ±<0.1
Born in another state	4,802 ±406	30.6% ±2.6	23.8% ±0.2	26.9% ±<0.1
Born a citizen outside the states	16 to 82	0.1% to 0.5%	0.7% ±<0.1	1.7% ±<0.1
Born abroad	2,215 ±237	14.1% ±1.5	5.9% ±0.1	14.1% ±<0.1
Naturalized citizens	455 ±137	2.9% ±0.9	2.6% ±0.1	7.4% ±<0.1
Not citizens	1,760 ±196	11.2% ±1.2	3.3% ±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 Iowa

48th of 99 by population, July 2025. Every one is listed on the Iowa page.

Counties of Iowa near Jefferson County in population, July 2025
County	July 2025	Change since 2020
Tama County	16,796	−1.5%
Iowa County	16,504	−1.0%
Hardin County	16,455	−2.2%
Crawford County	16,237	−1.5%
Clay County	16,202	−0.9%
Jefferson County	15,291	−2.5%
Hamilton County	14,944	−0.5%
Floyd County	14,901	−4.5%
Page County	14,856	−2.3%
Mills County	14,793	+2.6%
Harrison County	14,623	+0.4%

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

Compiled automatically from Census Bureau population estimates — counties and Puerto Rico municipios, with components of change and American Community Survey 5-year estimates — table-based Summary File by a checked SQL query · Editor: Kian O'Connor · How this site is built

Data retrieved September 25, 2026