Baltimore County area

Population and density of Baltimore County

The Census Bureau estimates that 847,650 people lived in Baltimore County on July 1, 2025. That ranks #75 of 3,222 county equivalents nationally and #3 of 24 in Maryland. Since the April 1, 2020 estimates base of 854,513, the population has declined by 6,863 (−0.8%), compared with +1.4% for Maryland as a whole.

With 598.4 square miles of land, that is 1,417 people per square mile (547 per km²), placing Baltimore County #127 nationally for density and #5 in Maryland. The median county equivalent has 47 people per square mile; the Maryland median is 335. Put another way, there are about 0.452 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 Baltimore County

Baltimore County has no incorporated cities, towns or villages. All 847,650 of its residents live in unincorporated communities, which the Census Bureau describes as census-designated places rather than municipalities.

Metropolitan area

Baltimore County is a central 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; Baltimore County accounts for 23% of the land and 29.7% 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

57 ZIP Code Tabulation Areas have land in Baltimore County; 44 of them have most of their land inside the county, and the others mainly cover neighboring areas.

210132102321030210312104321051210522105321057210712107421082210852108721093211022110421105211112111721120211282113121133211362115221153211552115621161211622116321204212062120721208212092121021212212152121921220212212122221224212272122821229212342123621237212392124421250212522128521286

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 Baltimore County

Baltimore County shares a land border with 6 county equivalents, including 1 in Pennsylvania. It has more land than 5 of them. The largest neighbor is York County (904.4 mi²) and the smallest is Baltimore city (80.9 mi²). Together with its neighbors, Baltimore County forms a block of 3,134.2 mi² of land, of which it holds 19.1%.

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

Baltimore 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. Maryland’s county land could hold about 16 areas the size of Baltimore 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 Baltimore County?

Baltimore County has more land than 1,595 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 Baltimore County at #1,487 nationally by total area, 140 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 12.2%, compared with a national county-equivalent median of 1.2% — 11.1 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 Baltimore 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.