Union County, SD Elevation & Topographic Map

Topographic elevation map of Union County, South Dakota, shaded from 1,070 ft on the southeast side to 1,540 ft on the north side
Elevation
1,540 ft 470 m1,420 ft 435 m1,360 ft 415 m1,250 ft 380 m1,130 ft 345 m1,070 ft 325 m
Contours every 500 ft, bold every 2,500 ft
USGS 3DEP · U.S. Census Bureau
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How to use this mapviews, tools and data
Elevation
Ground colored by height from green (lowest) to white (highest), with contour lines every 40–500 ft (USGS data).
Satellite
A 2016 satellite photo at 33 ft (10 m) detail; contours off.
3D
Tilt and turn the terrain; hills are raised 1.5×, or set ×1 for true height.
Click or tap anywhere
The exact elevation of that spot in ft and m.
Measure
Pick two points for the climb, descent and grade along a straight line.
County area
Fades everything outside the official county boundary (US Census).

Elevation Data

Union County averages about 1,240 ft (380 m) above sea level across all its land. Its ground runs from 1,070 ft on the southeast side to 1,540 ft on the north side.

Average elevation
1,240 ft 380 m
all land inside the county
Highest
1,540 ft 470 m
on the north side
Lowest
1,070 ft 325 m
on the southeast side

Union County spans about 470 ft of height, so no single spot tells the whole story. The ruler shows where most of its land lies, and where the other numbers you'll see come from.

FigureElevation
Average of all land1,240 ft380 m
Highest point
Inside the county, on the north side
1,540 ft470 m
Lowest point
Inside the county, on the southeast side
1,070 ft325 m

Elevation profile, south to north

42 mi south to north through Big Sioux Township.

Topographic Map

Topographic elevation map of Union County, South Dakota, shaded from 1,070 ft on the southeast side to 1,540 ft on the north side
County boundary (dashed) over shaded terrain, with contours every 40 ft (12 m).
Location
County in South Dakota, United States
Population
17,402 2024 est.
Land area
462.0 sq mi + 5.2 sq mi water
Density
38 per sq mi
Time zone
Central UTC−6 / −5
Landform region
Central Lowland
Drains to
Gulf of America
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Sources: U.S. Census Bureau, USGS

Nearby Places

Neighboring counties sharing a border, by average

  1. Dixon County, NE1,410 ft
  2. Lincoln County1,380 ft
  3. Sioux County, IA1,370 ft
  4. Plymouth County, IA1,320 ft
  5. Union County1,240 ft
  6. Dakota County, NE1,230 ft
  7. Clay County1,230 ft
  8. Woodbury County, IA1,230 ft

Rankings by average elevation

All 19 towns in Union County by typical elevation
  1. Beresford1,500 ft
  2. Prairie Township1,420 ft
  3. Alcester1,390 ft
  4. Alcester Township1,390 ft
  5. Big Springs Township1,370 ft
  6. Emmet Township1,360 ft
  7. Virginia Township1,290 ft
  8. Sioux Valley Township1,280 ft
  9. Spink Township1,260 ft
  10. Brule Township1,210 ft
  11. Richland1,130 ft
  12. Elk Point1,130 ft
  13. Elk Point Township1,120 ft
  14. Civil Bend Township1,120 ft
  15. Jefferson1,110 ft
  16. Jefferson Township1,110 ft
  17. North Sioux City1,110 ft
  18. Big Sioux Township1,090 ft
  19. Dakota Dunes1,090 ft
How we measure
  • Average: every USGS 3DEP bare-earth cell of land inside the Census county boundary (TIGER/Line, Jan 1 2026), weighted equally, on a 1 arc-second (≈100 ft, 30 m) grid. Land means the boundary minus Census area water.
  • Highest and lowest: the highest land cell. Lowest: the lowest land cell; coastal ground within 3 ft (1 m) of named tidal water counts as sea level.
  • Nearby Places: neighboring counties and rankings use each one's average elevation, on its own grid, the same figure its page shows. Peaks and hills: the highest summits inside the county with at least 980 ft (300 m) of prominence, then the highest federal (GNIS) summits inside it when there are fewer than 5; each is the 3DEP top on a ~7 ft (2 m) window, or the NGS published height when a usable survey mark sits within 160 ft (50 m) of it (shown as published).
  • Towns: each town's typical elevation (population-weighted median of its own 2020 blocks at 1 arc-second); a town is listed when any of its 2020 residents live in the county.
  • Rounding: computed heights are rounded to 10 ft (5 m), or to 1 ft (1 m) under 100 ft; 3DEP is good to about a meter, not a foot. Published figures (NGS survey heights) are shown as their publisher gives them.
  • Datum: North American Vertical Datum of 1988 (NAVD 88). NGS plans to replace NAVD 88 with a new datum (NAPGD2022); heights will then shift slightly.
  • Sources: USGS 3DEP, GNIS, Watershed Boundary Dataset and physiographic provinces; U.S. Census Bureau (TIGER boundaries and water, 2020 blocks, 2024 population estimates, county adjacency); NOAA NGS survey heights; BTS time zones. All public domain.