Union County, South Dakota Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 13th-largest in South Dakota
The population of Union County, South Dakota is 16,916 as of the 2023 American Community Survey, making it the 13th-largest county in South Dakota. The median household income is $84,137, the median home value is $269,500, and the median age is 40.4.
The population of Union County has grown 20.1% since 2010 (14,488 → 17,402), a +1.32% annualized rate.
16,916
Population
+1.32%
Annual growth
37
People / sq mi
$84,137
Median Income
$269,500
Median Home Value
Union County covers 461 sq mi of land at 36.7 people per square mile.
About Union County, SD
Union County is a county in South Dakota with a population of 16,916. It ranks #13 among counties in South Dakota by population. The median age is 40.4, older than the national median. The population is 51.1% male and 48.9% female.
The median household income in Union County is $84,137, above the US median of $74,580. 6.1% of residents live below the federal poverty level. Home values sit at a median of $269,500, with monthly rent averaging $1,055. The homeownership rate of 71.3% is higher than the national rate of 64.8%.
Educational attainment in Union County reflects 36.5% of adults 25 and older holding a bachelor's degree or higher, above the national average of 34.3%. Roughly 7.5% of workers primarily work from home, below the national work-from-home rate of 14.2%. The average commute is 18.6 minutes each way.
Union County Population History (2010-2024)
The county of Union County had a population of 14,488 in 2010 and 17,402 in 2024, a 20.1% growth over 14 years. The peak was 17,402 in 2024. Average annual growth rate: 1.33%.
17,402
Population (2024)
14,488
Population (2010)
17,402
Peak (2024)
1.33%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 14,488 |
| 2011 | 14,641 |
| 2012 | 14,801 |
| 2013 | 14,761 |
| 2014 | 14,996 |
| 2015 | 14,934 |
| 2016 | 15,174 |
| 2017 | 15,311 |
| 2018 | 15,616 |
| 2019 | 16,003 |
| 2020 | 16,857 |
| 2021 | 16,875 |
| 2022 | 17,083 |
| 2023 | 17,186 |
| 2024 | 17,402 |
Race & Ethnicity
| White | 90.4% |
| Black or African American | 0.8% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 2.3% |
| Two or More Races | 0.0% |
Age & Sex
40.4
Median Age
48.9%
Female
51.1%
Male
18.9%
Age 65+
Age Distribution
Children (under 15): 19.6% · Seniors (65+): 18.9%
Income & Poverty
| Median household income | $84,137+$11,716 vs state |
| Mean household income | $116,720 |
| Per-capita income | $49,563 |
| Poverty rate | 6.1%-1.3% vs state |
| Unemployment rate | 2.4% |
| Employment-to-population | 64.6% |
Top Industries by Employment
The largest employment sector in Union County is professional & business services, accounting for 23.8% of workers.
How residents commute
0.0%
Drive alone
1.4%
Carpool
82.5%
Public transit
7.5%
Work from home
18.6 min
Avg commute
Housing
$269,500+$32,700 vs state
Median home value
$1,055
Median rent
71.3%
Homeownership rate
7,438
Total housing units
95.8%
Occupied
4.2%
Vacant
28.7%
Renter-occupied
Social & access
94.8%
With health insurance
94.4%
With broadband internet
69.3%
Foreign-born
7.7%
Veterans (18+)
12.0%
With a disability
96.1%
Speak language other than English at home
Education
94.9%
High School+
36.5%
Bachelor's+
Largest cities in South Dakota
Other counties in South Dakota
Part of South Dakota
Metro areas in South Dakota
County rankings
Frequently Asked Questions
Union County, South Dakota has a population of 16,916 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 13th-largest county in South Dakota. Population density is 37 people per square mile.
The population of Union County has grown 20.1% since 2010 (14,488 → 17,402), a +1.32% annualized rate.
The median household income in Union County, South Dakota is $84,137, with mean (average) household income of $116,720 and per-capita income of $49,563. 6.1% of residents live below the federal poverty level.
In Union County, the largest racial and ethnic groups are White (90.4%), Hispanic or Latino (2.3%), Black or African American (0.8%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.
The median age in Union County, South Dakota is 40.4 years. Residents are 48.9% female and 51.1% male.
The median home value in Union County is $269,500 and median monthly rent is $1,055. 71.3% of occupied housing units are owner-occupied. The county has 7,438 total housing units, 4.2% of which are vacant.
The largest employment sector in Union County, South Dakota is professional, scientific, and management services, employing 23.8% of workers. The unemployment rate is 2.4%.
Sioux Falls is among the largest cities associated with Union County, South Dakota, with a population of 197,642.
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Full rankings of South Dakota counties
Statewide data for South Dakota
Population, race, income, age, and trends across South Dakota
Data from the American Community Survey (ACS) 5-Year estimates.
Source: U.S. Census Bureau ACS, 2026.