SD · GEOID 46051

Grant County area

Grant County, South Dakota covers 687.5 square miles: 681.4 square miles of land and 6.1 square miles of water.

Official Census measurements2026 Gazetteer · retrieved September 27, 2026
Land area681.4 mi²
Water area6.1 mi²
Total area687.5 mi²
National land rank#1376

County outline

Generalized outline of Grant County, South Dakota
2025 Census cartographic boundary, fitted to this frame. County maps are not at a common scale. The 2026 area measurements below come from the separate Gazetteer release. Map source and limitations.

Where Grant County is located

Grant County highlighted on a map of all U.S. county equivalents. About the maps

Area breakdown

Land accounts for 99.1% of Grant County’s measured area and water for 0.9%. Its combined area converts to 1,780.7 square kilometers or approximately 440,021 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land681.4461,764.937436,125.4
Water6.08715.7653,895.7
Total687.5331,780.702440,021.1

How Grant County compares

By original Census land area, Grant County ranks #48 of 66 in South Dakota and #1376 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 0.749 times the South Dakota county-equivalent median of 909.3 square miles. It accounts for 0.9% of the combined county land area in the state.

See the complete South Dakota ranking · What counts as a county equivalent?

What stands out about Grant County?

Grant County has more land than 1,846 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
Grant County681.4 mi²
South Dakota median909.3 mi²
National median604.5 mi²

A median is the middle county-equivalent measurement, not the average of the largest and smallest. All three bars use the same linear scale. Very small areas may appear as a thin sliver; the labels retain their values.

Does including water change its rank?

Using land plus water places Grant County at #1,472 nationally by total area, 96 places farther from the top than its land rank. Other county equivalents gain more area when their water measurements are included.

Its water share is 0.9%, compared with a national county-equivalent median of 1.2% — 0.3 percentage points lower. This describes the statistical geography’s land/water mix, not flood exposure or developable land.

Closest positions in the national land ranking

These entries sit immediately beside Grant County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#1375Chatham County, North Carolina681.5Compare
#1376Grant County, South Dakota681.4This county
#1377Cumberland County, Tennessee681.3Compare

Calculated from the same Census release as the area table. Total-area order uses original ALAND + AWATER; water shares and chart labels use published square miles. Calculation details.

Representative coordinates

The Census internal point is 45.172637, -96.772261. It represents a location inside the geography; it is not necessarily the centroid or the address of a courthouse.

Source and precision

U.S. Census Bureau, 2026 Gazetteer Files, Counties. Original ALAND: 1,764,937,283 m²; AWATER: 15,765,681 m². Rankings use ALAND; exact ties use ascending GEOID. Tables preserve Census-published square miles to three decimals, with conversions based on those values.

Download the official county source ZIP ↗ · Methodology

Common questions

How many acres of land are in Grant County?

The land measurement converts to approximately 436,125 acres. Including water, total area is approximately 440,021 acres. One square mile equals 640 acres.

Why might another source show a different area?

Check whether it reports land or total area, its Census vintage, and its rounding. Our guide explains how to reconcile county area figures.

Can this establish a property boundary?

No. Statistical measurements and generalized maps do not establish property lines. Consult the relevant local surveying or land-records authority.

Cite this county

Download the complete CSV or JSON dataset