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 distinguished by its share of foreign-born residents, 69.3% of the population. Union County is a county in South Dakota with a population of 16,916. It ranks #13 among counties in South Dakota by population.
Households take in a median $84,137, comfortably above the US median of $78,538. The poverty rate, 6.1%, is on the lower side for US counties and below the national 12.4%. A typical home is worth $269,500, with typical rent around $1,055.
About 36.5% of adults 25 and older have a bachelor’s degree, near the 35.0% national figure. Remote work is below the national 14.0% at 7.5%, and the average commute runs about 19 minutes each way.
The large foreign-born share is a defining thread in Union County, shaping language, household composition, and the labor force behind the economic figures above.
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.