Darke County area

Population and density of Darke County

The Census Bureau estimates that 51,520 people lived in Darke County on July 1, 2025. That ranks #1,005 of 3,222 county equivalents nationally and #49 of 88 in Ohio. Since the April 1, 2020 estimates base of 51,887, the population has declined by 367 (−0.7%), compared with +0.9% for Ohio as a whole.

With 598.1 square miles of land, that is 86 people per square mile (33 per km²), placing Darke County #1,105 nationally for density and #66 in Ohio. The median county equivalent has 47 people per square mile; the Ohio median is 120. Put another way, there are about 7.4 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 Darke County

21 incorporated places lie at least partly in Darke County. Together they are home to 25,372 people (49.2%); the other 26,148 (50.8%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Greenville city, with 12,680 residents in the county.

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

Metropolitan area

Darke County is a central county of the Greenville, OH Micropolitan Statistical Area. Darke County is the area’s only county equivalent, so the micro area has the same 598.1 square miles of land. By combined land it ranks #354 of 542 micropolitan areas, and #213 by population. It belongs to the Dayton-Springfield-Kettering, OH Combined Statistical Area.

ZIP codes

25 ZIP Code Tabulation Areas have land in Darke County; 16 of them have most of their land inside the county, and the others mainly cover neighboring areas.

45303453044530845309453104531845328453314533245337453384534645347453484535045351453524535845362453804538245388453904584645883

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 Darke County

Darke County shares a land border with 8 county equivalents, including 3 in Indiana. It has more land than every one of them. The largest neighbor is Mercer County (462.4 mi²) and the smallest is Jay County (383.9 mi²). Together with its neighbors, Darke County forms a block of 3,998.4 mi² of land, of which it holds 15%.

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

Darke County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.7 times as much. Ohio’s county land could hold about 68 areas the size of Darke County.

Another way to picture it: the same land area would fill a square about 24.5 miles (39.4 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 Darke County?

Darke County has more land than 1,591 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 Darke County at #1,746 nationally by total area, 115 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 0.3%, compared with a national county-equivalent median of 1.2% — 0.9 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 Darke 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.