Brown County area

Population and density of Brown County

The Census Bureau estimates that 37,561 people lived in Brown County on July 1, 2025. That ranks #1,279 of 3,222 county equivalents nationally and #5 of 66 in South Dakota. Since the April 1, 2020 estimates base of 38,302, the population has declined by 741 (−1.9%), compared with +5.5% for South Dakota as a whole.

With 1,713 square miles of land, that is 22 people per square mile (8.5 per km²), placing Brown County #2,258 nationally for density and #12 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 29 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 Brown County

10 incorporated places lie at least partly in Brown County. Together they are home to 30,549 people (81.3%); the other 7,012 (18.7%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Aberdeen city, with 27,961 residents in the county.

Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside Brown County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.

Metropolitan area

Brown County is a central county of the Aberdeen, SD Micropolitan Statistical Area. Its 2 county equivalents have 41,583 residents on 2,839 square miles of land; Brown County accounts for 60.3% of the land and 90.3% of the residents. By combined land it ranks #54 of 542 micropolitan areas, and #309 by population.

ZIP codes

20 ZIP Code Tabulation Areas have land in Brown County; 14 of them have most of their land inside the county, and the others mainly cover neighboring areas.

5740157422574265742757432574335743457439574415744557446574495745157460574615747457479574815843658439

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 Brown County

Brown County shares a land border with 8 county equivalents, including 2 in North Dakota. It has more land than every one of them. The largest neighbor is Spink County (1,503.5 mi²) and the smallest is Marshall County (838.1 mi²). Together with its neighbors, Brown County forms a block of 10,317.4 mi² of land, of which it holds 16.6%.

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

Brown County has more land than 1 of the 50 states. It is about 1.7 times the land area of Rhode Island (1,033.9 mi²), while Delaware, the next larger state, has 1.1 times as much land (1,948.6 mi²). South Dakota’s county land could hold about 44 areas the size of Brown County.

Another way to picture it: the same land area would fill a square about 41.4 miles (66.6 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 Brown County?

Brown County has more land than 2,873 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 Brown County at #389 nationally by total area, 40 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 1%, compared with a national county-equivalent median of 1.2% — 0.1 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 Brown 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.