Demographics of Union County, South Dakota

Union County, South Dakota had 17,402 people on July 1, 2025, by the Census Bureau’s estimate: +547 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.

Union County, in four figures

17,402
Population: July 1, 2025, Vintage 2025 estimate.; +3.2%
Change since July 2020: +547 people.; 41.5 ±1.3
Median age: ACS 2020–⁠2024.; $89,636 ±$5,949
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.

Union County, South Dakota's population grew 3.2% from July 2020 to July 2025, against +3.1% nationally

The July 1 estimate of Union County, South Dakota'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

Union County, South Dakota's population grew 3.2% from July 2020 to July 2025, against +3.1% nationally. The July 1 estimate of Union County, South Dakota'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	16,855	100.0	100.0
2021	16,881	100.2	100.2
2022	17,079	101.3	100.7
2023	17,149	101.7	101.6
2024	17,373	103.1	102.5
2025	17,402	103.2	103.1

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Population of Union County, South Dakota on July 1 of each year, Vintage 2025
July 1	Population	Change	Births less deaths	From abroad	From elsewhere in the country
2020	16,855	+42	+13	0	+27
2021	16,881	+26	+7	+14	−11
2022	17,079	+198	+18	+36	+149
2023	17,149	+70	+38	+15	+21
2024	17,373	+224	+71	+51	+104
2025	17,402	+29	+104	+39	−115

Age, 2020–2024

The median age is 41.5 ±1.3: for men 39.7 ±1.2 and for women 42.8 ±1.0. Shares are of everyone the survey counts, in the Bureau’s sex-by-age table (B01001).

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People in Union County by age, ACS 2020–2024
Age	People	Share	South Dakota	United States
Under 5	869 ±39	5.1% ±0.2	6.3% ±0.1	5.6% ±<0.1
5 to 17	3,239 ±295	19.0% ±1.7	17.9% ±0.2	16.3% ±<0.1
18 to 24	1,131 ±120	6.6% ±0.7	9.3% ±0.4	9.1% ±<0.1
25 to 44	4,317 ±348	25.3% ±2.0	25.2% ±0.2	26.9% ±<0.1
45 to 64	4,197 ±258	24.6% ±1.5	23.3% ±0.2	24.8% ±<0.1
65 and over	3,328 ±289	19.5% ±1.7	18.0% ±0.3	17.2% ±<0.1

Income and poverty, 2020–2024

Median household income is $89,636 ±$5,949, and income per person $53,834 ±$4,396, in 2024 dollars. The median is $75,081 ±$888 in South Dakota and $80,734 ±$166 in the United States.

Households by income

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Households in Union County by income, ACS 2020–2024
Household income	Households	Share	South Dakota	United States
Under $25,000	812 ±191	11.1% ±2.6	14.0% ±0.4	14.6% ±<0.1
$25,000 to $49,999	1,064 ±211	14.6% ±2.9	18.5% ±0.5	16.7% ±<0.1
$50,000 to $74,999	1,052 ±194	14.4% ±2.7	17.4% ±0.4	15.5% ±<0.1
$75,000 to $99,999	1,215 ±242	16.6% ±3.3	14.6% ±0.4	12.6% ±<0.1
$100,000 to $149,999	1,390 ±240	19.0% ±3.3	18.9% ±0.5	17.5% ±<0.1
$150,000 to $199,999	817 ±181	11.2% ±2.5	8.5% ±0.3	9.6% ±<0.1
$200,000 or more	960 ±231	13.1% ±3.2	8.1% ±0.4	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 Union County by age, ACS 2020–2024
Age	Below poverty	Rate	South Dakota	United States
All ages	1,049 ±235	6.2% ±1.4	11.9% ±0.4	12.5% ±0.1
Under 18	44 to 224	1.1% to 5.5%	14.3% ±0.6	16.1% ±0.1
18 to 59	493 ±172	5.8% ±2.0	11.8% ±0.5	11.6% ±0.1
60 and over	422 ±158	9.8% ±3.6	9.7% ±0.4	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 Union County, ACS 2020–2024
Measure	Union County	South Dakota	United States
Housing units	7,588 ±28	408,584 ±422	143,775,355 ±10,234
Occupied	96.3% ±1.5	89.5% ±0.4	89.9% ±0.1
Vacant	3.7% ±1.6	10.5% ±0.4	10.1% ±0.1
Owner occupied	73.1% ±2.9	68.6% ±0.5	65.2% ±0.3
Renter occupied	26.9% ±3.3	31.4% ±0.5	34.8% ±0.1
Median home value	$301,100 ±$18,340	$257,400 ±$3,051	$332,700 ±$236
Median gross rent	$1,069 ±$63	$946 ±$11	$1,413 ±$2
Median year built	1993 ±2	1980 ±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 Union County by Hispanic origin and race, ACS 2020–2024
Origin	People	Share	South Dakota	United States
Hispanic or Latino	823 ±0	4.8% ±<0.1	4.8% ±<0.1	19.3% ±<0.1
White alone, not Hispanic	15,101 ±160	88.4% ±0.9	79.8% ±0.1	57.4% ±<0.1
Black alone, not Hispanic	79 to 241	0.5% to 1.4%	2.1% ±0.1	11.9% ±<0.1
Asian alone, not Hispanic	190 ±93	1.1% ±0.5	1.4% ±0.1	5.9% ±<0.1
American Indian and Alaska Native alone, not Hispanic	127 ±57	0.7% ±0.3	7.1% ±0.1	0.5% ±<0.1
Native Hawaiian and Other Pacific Islander alone, not Hispanic	0 to 46	0% to 0.3%	< 0.1% ±<0.1	0.2% ±<0.1
Some other race alone, not Hispanic	0 to 69	0% to 0.4%	0.3% ±0.1	0.6% ±<0.1
Two or more races, not Hispanic	635 ±204	3.7% ±1.2	4.4% ±0.2	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 Union County by place of birth and citizenship, ACS 2020–2024
Born	People	Share	South Dakota	United States
Born in the state	4,409 ±446	25.8% ±2.6	62.4% ±0.4	57.3% ±<0.1
Born in another state	12,241 ±470	71.7% ±2.8	32.9% ±0.4	26.9% ±<0.1
Born a citizen outside the states	20 to 158	0.1% to 0.9%	0.7% ±0.1	1.7% ±<0.1
Born abroad	342 ±148	2.0% ±0.9	4.0% ±0.2	14.1% ±<0.1
Naturalized citizens	49 to 175	0.3% to 1.0%	1.7% ±0.1	7.4% ±<0.1
Not citizens	95 to 365	0.6% to 2.1%	2.3% ±0.2	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%.

Union County among the counties of South Dakota

13th of 66 by population, July 2025. Every one is listed on the South Dakota page.

Counties of South Dakota near Union County in population, July 2025
County	July 2025	Change since 2020
Lawrence County	29,459	+14.0%
Yankton County	23,635	+1.5%
Davison County	20,069	+0.5%
Beadle County	19,624	+2.4%
Hughes County	17,570	−0.9%
Union County	17,402	+3.2%
Clay County	15,031	+0.2%
Oglala Lakota County	13,338	−2.3%
Lake County	10,993	−0.2%
Butte County	10,856	+5.5%
Roberts County	10,255	−0.1%

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