Buffalo County area

Population and density of Buffalo County

The Census Bureau estimates that 1,802 people lived in Buffalo County on July 1, 2025. That ranks #3,134 of 3,222 county equivalents nationally and #59 of 66 in South Dakota. Since the April 1, 2020 estimates base of 1,943, the population has declined by 141 (−7.3%), compared with +5.5% for South Dakota as a whole.

With 471.4 square miles of land, that is 3.8 people per square mile (1.5 per km²), placing Buffalo County #2,918 nationally for density and #44 in South Dakota. The median county equivalent has 47 people per square mile; the South Dakota median is 5.7. Put another way, there are about 167 acres of land per resident.

U.S. Census Bureau, Vintage 2025 population estimates. Estimates are revised each year and are not decennial census counts. Density divides the whole population by the whole county’s land area, so it describes an average, not how settlement is distributed within the county. Population sources and methods.

Cities and towns in Buffalo County

Buffalo County has no incorporated cities, towns or villages. All 1,802 of its residents live in unincorporated communities, which the Census Bureau describes as census-designated places rather than municipalities.

Metropolitan area

Buffalo County is not part of any metropolitan or micropolitan statistical area in the Office of Management and Budget’s July 2023 delineation; 1,306 other county equivalents are also outside one. These areas are built around an urban core of at least 10,000 people plus the counties tied to it by commuting, so counties outside them are generally rural.

ZIP codes

6 ZIP Code Tabulation Areas have land in Buffalo County; 2 of them have most of their land inside the county, and the others mainly cover neighboring areas.

573255733957341573555736257370

ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Lighter codes have less than half of their land in this county. Post-office-box and single-address ZIP Codes have no tabulation area.

Counties bordering Buffalo County

Buffalo County shares a land border with 5 county equivalents. Each of them has more land than Buffalo County. The largest neighbor is Lyman County (1,642.3 mi²) and the smallest is Jerauld County (526.1 mi²). Together with its neighbors, Buffalo County forms a block of 5,754.3 mi² of land, of which it holds 8.2%.

How big is Buffalo County compared with U.S. states?

Buffalo County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 2.2 times as much. South Dakota’s county land could hold about 161 areas the size of Buffalo County.

Another way to picture it: the same land area would fill a square about 21.7 miles (34.9 km) on each side. Real county shapes are rarely square, so this is a scale reference rather than a width or driving distance.

State figures are the sums of each state’s county-equivalent land measurements in the same Census release, so states and counties are compared on the same basis. Published state totals can differ slightly because of rounding. Compare all states · Counties bigger than entire states.

What stands out about Buffalo County?

Buffalo County has more land than 1,036 of the other 3,221 county equivalents in the dataset.

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 Buffalo County at #2,222 nationally by total area, 36 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 3.4%, compared with a national county-equivalent median of 1.2% — 2.2 percentage points higher. 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 Buffalo County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

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.