County · South Dakota
Union County, South Dakota
Union County, South Dakota. Union County had 17,402 residents in 2025 by the Census Bureau's estimate, up 3.5% since 2020, slower than South Dakota (+5.5%). It holds 19 places (5 cities, villages and boroughs, 12 towns and townships and 2 census-designated) and 4 census tracts. GEOID 46127.
Union County is one of the 3 counties of the Sioux City, IA-NE-SD metropolitan statistical area (the Census Bureau's July 2023 delineation).
Residents, July 2025 estimate
17,402
Census Bureau estimate (no margin published)
2020 Census count: 16,811 · ACS 2020-2024: 17,081
Median household income
$89,636
±$5,949 (90% margin)
South Dakota: $75,081
Median home value
$301,100
±$18,340 (90% margin)
South Dakota: $257,400
Median gross rent
$1,069
±$63 (90% margin)
South Dakota: $946
How many people live in Union County, and is it growing?
The 2020 Census counted 16,811 residents in Union County. The Census Bureau estimates 17,402 for July 1, 2025, up 3.5% since 2020, slower than South Dakota (+5.5%). The 2020-2024 American Community Survey puts the population at 17,081 over 461 square miles of land.
| Measure | Union County | South Dakota | Change since 2015-2019 |
|---|---|---|---|
| Total population | 17,081 | 907,428 | +1,713 |
| Households | 7,310±118 | 365,544 | +691 |
| Average household size | 2.32±0.04 | 2.39 | no clear change |
| Housing units | 7,588±28 | 408,584 | +452 |
Union County's population since 2000
From 12,584 in 2000 to 17,402 in 2025: up 38.3%. The 2000, 2010 and 2020 figures are census counts. The 2005 figure is the Census Bureau's intercensal estimate, revised to fit the 2000 and 2010 counts and drawn on 2010 boundaries; 2015 and 2025 are July 1 estimates made from the census before them.
Source: The 2000, 2010 and 2020 Census counts and the Census Bureau's population estimates (intercensal 2000-2010, Vintage 2020, Vintage 2025) · Census population estimates
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); PEP Vintage 2025 (CO-EST2025); 2020 Census · Check it at data.census.gov
What cities and towns are in Union County?
Union County holds 19 places: 5 cities, villages and boroughs (incorporated places), 12 towns and townships (county subdivisions with their own government) and 2 census-designated places. The largest is Big Sioux Township with 5,152 residents (2025 estimate). Places that cross a county line are listed with the share of their 2020 residents who live in this county.
| Big Sioux Township | 4,683 | $128,005 |
|---|---|---|
| Dakota Dunes | 4,020 | $136,125 |
| North Sioux City | 3,042 | $71,908 |
| Elk Point | 2,149 | $90,473 |
| Beresford | 2,180 | $78,793 |
| Jefferson Township, Union CountyGEOID 4612732740 | 1,115 | $196,442 |
| Alcester | 820 | $57,000 |
| JeffersonGEOID 4632700 | 475 | $82,888 |
| Civil Bend TownshipGEOID 4612711980 | 316 | not published |
| Alcester TownshipGEOID 4612700740 | 285 | $110,156 |
| Prairie TownshipGEOID 4612751540 | 262 | not published |
| Elk Point TownshipGEOID 4612718660 | 258 | $109,500 |
| Emmet TownshipGEOID 4612719500 | 253 | $117,500 |
| Brule Township, Union CountyGEOID 4612707860 | 237 | $250,000 or more |
| Virginia TownshipGEOID 4612767580 | 231 | $110,655 |
| Sioux Valley TownshipGEOID 4612759140 | 225 | not published |
| Big Springs TownshipGEOID 4612705460 | 212 | $96,103 |
| Spink TownshipGEOID 4612760140 | 211 | $44,801 |
| RichlandGEOID 4654750 | 97 | $130,417 |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); 2020 place-by-county parts · Check it at data.census.gov
Who lives in Union County?
The median resident of Union County is 41.5 years old; 24.1% are under 18 and 19.5% are 65 or older. The largest group is non-Hispanic white residents at 88.4%, then Hispanic or Latino residents (of any race) at 4.8%. 2.0% of residents were born outside the United States.
| Measure | Union County | South Dakota | Change since 2015-2019 |
|---|---|---|---|
| Median age | 41.5±1.3 | 38.0 | +1.5 |
| Under 18 years | 24.1% | 24.2% | – |
| 65 years and over | 19.5%±0.5 pts | 18.0% | – |
| Hispanic or Latino (any race) | 4.8% | 4.8% | +1.6 pts |
| White alone, not Hispanic | 88.4%±0.9 pts | 79.8% | −3.7 pts |
| Black or African American alone, not Hispanic | 0.9%±0.5 pts | 2.1% | no clear change |
| Asian alone, not Hispanic | 1.1%±0.5 pts | 1.4% | no clear change |
| American Indian and Alaska Native alone, not Hispanic | 0.7%±0.3 pts | 7.1% | – |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.1%±0.2 pts | 0.0% | – |
| Two or more races, not Hispanic | 3.7%±1.2 pts | 4.4% | – |
| Some other race alone, not Hispanic | 0.2%±0.2 pts | 0.3% | – |
| Born outside the United States | 2.0%±0.9 pts | 4.0% | no clear change |
| Speak a language other than English at home (age 5+) | 3.0%±1.0 pts | 7.1% | – |
| Civilian veterans (age 18+) | 7.6%±1.8 pts | 7.9% | – |
| With a disability | 10.8%±2.2 pts | 12.5% | – |
| No health insurance coverage | 5.1%±1.6 pts | 9.0% | no clear change |
| High school graduate or higher (age 25+) | 95.7%±0.9 pts | 93.2% | – |
| Bachelor's degree or higher (age 25+) | 37.0%±3.3 pts | 31.9% | +6.4 pts |
| Graduate or professional degree (age 25+) | 13.3%±3.0 pts | 10.0% | – |
| Moved from another state in the past year | 4.8%±2.2 pts | 3.2% | – |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profiles DP02, DP05) · Check it at data.census.gov
What do households in Union County earn?
Half of Union County's 7,310 households earn less than $89,636 a year (±$5,949), against $75,081 in South Dakota. In 2015-2019 it was $86,614 in 2024 dollars; the margins of error cannot tell the two periods apart. 6.2% of residents live below the poverty line.
| Measure | Union County | South Dakota | Change since 2015-2019 |
|---|---|---|---|
| Median household income | $89,636±$5,949 | $75,081 | no clear change |
| Mean household income | $124,814±$9,694 | $98,527 | – |
| Per capita income | $53,834±$4,396 | $40,550 | no clear change |
| People below the poverty line | 6.2%±1.4 pts | 11.9% | −2.4 pts |
| Children under 18 below the poverty line | 3.3%±2.3 pts | 14.3% | – |
| Households receiving SNAP | 4.1%±1.5 pts | 7.9% | – |
| Households with a broadband subscription | 89.5%±2.5 pts | 89.6% | – |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov
What does housing cost in Union County?
Owners occupy 73.1% of Union County's occupied homes and renters 26.9%. The median owner-occupied home is valued at $301,100 by its owner (±$18,340). The median renter pays $1,069 a month including utilities, and 25.3% of renters pay 35% or more of their income on rent.
| Measure | Union County | South Dakota | Change since 2015-2019 |
|---|---|---|---|
| Median home value (owner-occupied) | $301,100±$18,340 | $257,400 | +$80,437 |
| Median gross rent | $1,069±$63 | $946 | no clear change |
| Renters paying 35% or more of income on rent | 25.3%±7.3 pts | 30.4% | no clear change |
| Median monthly owner costs, with a mortgage | $1,758±$129 | $1,680 | – |
| Owner-occupied homes | 73.1%±3.2 pts | 68.6% | no clear change |
| Housing units | 7,588±28 | 408,584 | +452 |
| Homeowner vacancy rate | 0.4%±0.7 pts | 0.8% | – |
| Rental vacancy rate | 1.7%±1.7 pts | 6.0% | – |
| Single-family detached homes | 72.0%±2.6 pts | 66.9% | – |
| Mobile homes | 4.2%±1.5 pts | 7.2% | – |
| Built 2020 or later | 1.2%±0.9 pts | 2.3% | – |
| Built 1939 or earlier | 16.0%±2.4 pts | 15.8% | – |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP04) · Check it at data.census.gov
How many new homes is Union County building?
Builders took permits for 277 new housing units across Union County in 2025 (47 single-family), 15.9 per 1,000 residents.
Source: Building Permits Survey, annual county files 2019-2025, U.S. Census Bureau · Census Building Permits Survey
How do people in Union County get to work?
82.6% of Union County's workers drive alone and 7.9% work from home. The average trip to work takes 17.7 minutes. The unemployment rate in 2020-2024 averaged 3.0%.
| Measure | Union County | South Dakota | Change since 2015-2019 |
|---|---|---|---|
| In the labor force (age 16+) | 68.4%±2.1 pts | 67.2% | – |
| Unemployment rate | 3.0%±1.6 pts | 2.9% | no clear change |
| Drove alone to work | 82.6%±2.7 pts | 77.0% | – |
| Carpooled | 6.8%±1.8 pts | 8.3% | – |
| Public transportation | 0.0%±0.3 pts | 0.5% | – |
| Walked | 1.3%±0.7 pts | 3.1% | – |
| Worked from home | 7.9%±2.3 pts | 9.7% | no clear change |
| Mean travel time to work | 17.7 min±1.2 | 17.8 min | no clear change |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov
What are Union County's census tracts?
Union County is divided into 4 census tracts. Among those with a reliable estimate, median household income runs from $77,825 (Tract 201) to $117,257 (Tract 203.01).
| Tract 20146127020100 | 4,229±293 | $77,825 |
|---|---|---|
| Tract 20246127020200 | 3,057±252 | $94,637 |
| Tract 203.0146127020301 | 4,982±273 | $117,257 |
| Tract 203.0246127020302 | 4,813±412 | $84,013 |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) · Check it at data.census.gov
How does Union County compare with South Dakota's other counties?
| Measure | Rank |
|---|---|
| Population | 13th of 66 |
| Growth 2020-2025 | 16th of 66 |
| Residents per square mile | 8th of 66 |
| Median household income | 2nd of 66 |
| Median home value | 6th of 66 |
| Median gross rent | 5th of 65 |
| Poverty rate | 60th of 65 |
| Bachelor's degree or higher | 5th of 66 |
| Median age | 33rd of 66 |
Source: PlainCities ranks from the American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) and PEP Vintage 2025 · How ranks are computed
How these figures are made: methodology and release checks · reading a margin of error · every state · corrections
Not on this page: crime, weather and schools for Union County are other agencies' records. Crime: the FBI's Crime Data Explorer · climate: NOAA's U.S. Climate Normals · schools: the National Center for Education Statistics' school search.