Dewey County area

Population and density of Dewey County

The Census Bureau estimates that 5,419 people lived in Dewey County on July 1, 2025. That ranks #2,862 of 3,222 county equivalents nationally and #33 of 66 in South Dakota. Since the April 1, 2020 estimates base of 5,244, the population has grown by 175 (+3.3%), compared with +5.5% for South Dakota as a whole.

With 2,302.4 square miles of land, that is 2.4 people per square mile (0.91 per km²), placing Dewey County #3,032 nationally for density and #50 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 272 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 Dewey County

3 incorporated places lie at least partly in Dewey County. Together they are home to 1,371 people (25.3%); the other 4,048 (74.7%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Eagle Butte city, with 661 residents in the county (the city extends into 1 other county). The county seat, Timber Lake city, has 548 residents.

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

Metropolitan area

Dewey 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

10 ZIP Code Tabulation Areas have land in Dewey County; 7 of them have most of their land inside the county, and the others mainly cover neighboring areas.

57442576015762557630576335763657652576565765757661

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 Dewey County

Dewey County shares a land border with 6 county equivalents. It has more land than 5 of them. The largest neighbor is Corson County (2,469.7 mi²) and the smallest is Walworth County (707.5 mi²). Together with its neighbors, Dewey County forms a block of 10,753.1 mi² of land, of which it holds 21.4%.

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

Dewey County has more land than 2 of the 50 states. It is about 1.2 times the land area of Delaware (1,948.6 mi²), while Connecticut, the next larger state, has 2.1 times as much land (4,842.5 mi²). South Dakota’s county land could hold about 33 areas the size of Dewey County.

Another way to picture it: the same land area would fill a square about 48 miles (77.2 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 Dewey County?

Dewey County has more land than 2,980 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 Dewey County at #240 nationally by total area, 2 places closer to the top than its land rank. The water assigned to this geography moves it ahead of some county equivalents with more land.

Its water share is 5.8%, compared with a national county-equivalent median of 1.2% — 4.7 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 Dewey 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.