Harford County area

Population and density of Harford County

The Census Bureau estimates that 266,446 people lived in Harford County on July 1, 2025. That ranks #279 of 3,222 county equivalents nationally and #8 of 24 in Maryland. Since the April 1, 2020 estimates base of 260,933, the population has grown by 5,513 (+2.1%), compared with +1.4% for Maryland as a whole.

With 437.1 square miles of land, that is 610 people per square mile (235 per km²), placing Harford County #287 nationally for density and #7 in Maryland. The median county equivalent has 47 people per square mile; the Maryland median is 335. Put another way, there are about 1 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 Harford County

3 incorporated places lie at least partly in Harford County. Together they are home to 44,511 people (16.7%); the other 221,935 (83.3%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Aberdeen city, with 18,374 residents in the county. The county seat, Bel Air town, has 10,507 residents. Among places with at least 1,000 residents in 2020, Aberdeen city grew fastest since then (+12.7%).

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

Metropolitan area

Harford County is an outlying county of the Baltimore-Columbia-Towson, MD Metropolitan Statistical Area. Its 7 county equivalents have 2,857,781 residents on 2,601.5 square miles of land; Harford County accounts for 16.8% of the land and 9.3% of the residents. By combined land it ranks #125 of 393 metropolitan areas, and #22 by population. It belongs to the Washington-Baltimore-Arlington, DC-MD-VA-WV-PA Combined Statistical Area.

ZIP codes

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

210012100521009210102101321014210152101721028210342104021047210502107821082210842108521087211112113021132211542116021161

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 Harford County

Harford County shares a land border with 3 county equivalents, including 1 in Pennsylvania. It has more land than 1 of them. The largest neighbor is York County (904.4 mi²) and the smallest is Cecil County (346.3 mi²). Together with its neighbors, Harford County forms a block of 2,286.1 mi² of land, of which it holds 19.1%.

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

Harford County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 2.4 times as much. Maryland’s county land could hold about 22 areas the size of Harford County.

Another way to picture it: the same land area would fill a square about 20.9 miles (33.6 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 Harford County?

Harford County has more land than 904 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 Harford County at #2,082 nationally by total area, 236 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 17%, compared with a national county-equivalent median of 1.2% — 15.8 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 Harford 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.