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Union County, South Dakota

Union County profile, demographic data, and geographic information.

Union County is a county located in South Dakota, United States of America. As of official census estimates, it has a reported population of 17,402. The land area covers 461.98 sq mi. [1]

Local Government Administration U.S. Census Bureau GMAF

County Of Union County
Official Title: Chairman Of Board
Address: 209 E MAIN ST, STE 200, ELK POINT SD 57025-2327

Demographics & Population

Demographic Metric Estimate / Count Margin of Error Survey Period / Source
Total Population (2025 PEP Estimate) 17,402 — 2025 / Census
Median Age 41.5 yrs ±1.3 2020-2024 / Census ACS 5-Year 2024
Total Households 7,310 ±118 2020-2024 / Census ACS 5-Year 2024
Source: U.S. Census Bureau (PEP, ACS 5-Year).

Housing & Real Estate Profile

Housing Metric Estimate / Value Margin of Error
Total Housing Units 7,588 ±28
Occupied Housing Units 7,310 ±118
Vacant Housing Units 278 ±122
Median Home Value $301,100 ±$18,340
Median Gross Rent $1,069 ±$63
Source: U.S. Census Bureau ACS 5-Year (2020-2024).

Economy & Workforce

Economic Metric Estimate / Value Margin of Error
Median Household Income $89,636 ±$5,949
Per Capita Income $53,834 ±$4,396
Poverty Rate 6.2% ±1.4%
Population Below Poverty Level 1,049 ±235
Unemployment Rate 3% ±1.6%
Civilian Labor Force, Employed 8,947 ±335
Broadband Internet Rate 89.5% ±2.5%
Source: U.S. Census Bureau ACS 5-Year (2020-2024).

Climate & Weather Observations

NOAA Monthly Climate Normals

Observation Station: Climate data reflects NOAA 1991–2020 standard normals recorded at VERMILLION 2 SE, SD US, located 14.4 miles from Union County. Local microclimates, topography, and elevation may cause municipal conditions to differ.
Month High (°F) Low (°F) Mean (°F) Precip (in) Snow (in)
January 30.5° 10.2° 20.4° 0.53" —
February 36.1° 14.0° 25.0° 0.70" —
March 48.4° 25.2° 36.8° 1.42" —
April 61.9° 36.0° 48.9° 3.09" —
May 72.7° 48.1° 60.4° 3.96" —
June 82.2° 59.1° 70.7° 4.30" —
July 85.5° 63.2° 74.4° 3.61" —
August 83.3° 60.7° 72.0° 2.88" —
September 78.1° 51.8° 64.9° 3.07" —
October 64.6° 38.5° 51.6° 2.35" —
November 48.2° 25.2° 36.7° 1.30" —
December 34.0° 14.6° 24.3° 0.79" —
Source: NOAA U.S. Climate Normals (1991–2020).

Local Weather Forecast

Weather forecast data is currently unavailable in the local cache.

Sources & Data Provenance

  1. Geographic Classification & Identifiers: U.S. Census Bureau Gazetteer (2026) and TIGER/Line Shapefiles. GEOID: 46127. • Official Source Dataset →
  2. Socioeconomic & Housing Metrics: U.S. Census Bureau American Community Survey (ACS) 5-year estimates and Population Estimates Program (PEP). Margin of Error (MOE) intervals are reported where published; suppressed values are never estimated or replaced with false zeros.
  3. Civic Directory Datasets: Centers for Medicare & Medicaid Services (CMS Hospital Directory), National Center for Education Statistics (NCES IPEDS Postsecondary Directory), and Institute of Museum and Library Services (IMLS Public Libraries Survey). Airport landing facilities are provided by airport-data.com.
  4. Weather & Climate Observations: National Oceanic and Atmospheric Administration (NOAA) U.S. Climate Normals 1991–2020 and National Weather Service (NWS) point forecasts.