Delaware County area

Population and density of Delaware County

The Census Bureau estimates that 242,032 people lived in Delaware County on July 1, 2025. That ranks #302 of 3,222 county equivalents nationally and #11 of 88 in Ohio. Since the April 1, 2020 estimates base of 214,141, the population has grown by 27,891 (+13%), compared with +0.9% for Ohio as a whole.

With 443.1 square miles of land, that is 546 people per square mile (211 per km²), placing Delaware County #319 nationally for density and #12 in Ohio. The median county equivalent has 47 people per square mile; the Ohio median is 120. Put another way, there are about 1.2 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 Delaware County

10 incorporated places lie at least partly in Delaware County. Together they are home to 107,064 people (44.2%); the other 134,968 (55.8%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Delaware city, with 46,636 residents in the county. By land, Columbus city is the largest at 222.9 mi² across all its counties. Among places with at least 1,000 residents in 2020, Sunbury city grew fastest since then (+33.6%).

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

Metropolitan area

Delaware County is a central county of the Columbus, OH Metropolitan Statistical Area. Its 10 county equivalents have 2,242,028 residents on 4,797.5 square miles of land; Delaware County accounts for 9.2% of the land and 10.8% of the residents. By combined land it ranks #55 of 393 metropolitan areas, and #32 by population. It belongs to the Columbus-Marion-Zanesville, OH Combined Statistical Area.

ZIP codes

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

430034301143013430154301643017430214303143032430354304043054430614306543066430744308143082432354324043334433424334443356

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 Delaware County

Delaware County shares a land border with 6 county equivalents. It has more land than 3 of them. The largest neighbor is Licking County (682.4 mi²) and the smallest is Marion County (403.8 mi²). Together with its neighbors, Delaware County forms a block of 3,425.2 mi² of land, of which it holds 12.9%.

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

Delaware County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 2.3 times as much. Ohio’s county land could hold about 92 areas the size of Delaware County.

Another way to picture it: the same land area would fill a square about 21.1 miles (33.9 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 Delaware County?

Delaware County has more land than 929 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 Delaware County at #2,318 nationally by total area, 25 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 3.1%, compared with a national county-equivalent median of 1.2% — 1.9 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 Delaware 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.