Arlington County area

Population and density of Arlington County

The Census Bureau estimates that 243,931 people lived in Arlington County on July 1, 2025. That ranks #301 of 3,222 county equivalents nationally and #8 of 133 in Virginia. Since the April 1, 2020 estimates base of 238,647, the population has grown by 5,284 (+2.2%), compared with +2.9% for Virginia as a whole.

With 26 square miles of land, that is 9,383 people per square mile (3,623 per km²), placing Arlington County #11 nationally for density and #2 in Virginia. The median county equivalent has 47 people per square mile; the Virginia median is 109. Put another way, there are about 0.068 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 Arlington County

Arlington County has no incorporated cities, towns or villages. All 243,931 of its residents live in unincorporated communities, which the Census Bureau describes as census-designated places rather than municipalities.

Metropolitan area

Arlington County is a central county of the Washington-Arlington-Alexandria, DC-VA-MD-WV Metropolitan Statistical Area, in the Arlington-Alexandria-Reston, VA-WV metropolitan division. Its 23 county equivalents have 6,465,724 residents on 6,033.7 square miles of land; Arlington County accounts for 0.4% of the land and 3.8% of the residents. By combined land it ranks #35 of 393 metropolitan areas, and #7 by population. It belongs to the Washington-Baltimore-Arlington, DC-MD-VA-WV-PA Combined Statistical Area.

ZIP codes

12 ZIP Code Tabulation Areas have land in Arlington County; 11 of them have most of their land inside the county, and the others mainly cover neighboring areas.

221012220122202222032220422205222062220722209222112221322214

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 Arlington County

Arlington County shares a land border with 4 county equivalents, including 1 in District of Columbia. It has more land than 2 of them. The largest neighbor is Fairfax County (391 mi²) and the smallest is Falls Church city (2 mi²). Together with its neighbors, Arlington County forms a block of 495.1 mi² of land, of which it holds 5.3%.

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

Arlington County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 40 times as much. Virginia’s county land could hold about 1,519 areas the size of Arlington County.

Another way to picture it: the same land area would fill a square about 5.10 miles (8.2 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 Arlington County?

Arlington County has more land than 44 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 Arlington County at #3,192 nationally by total area, 14 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 0.4%, compared with a national county-equivalent median of 1.2% — 0.8 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 Arlington 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.