Montgomery County area

Population and density of Montgomery County

The Census Bureau estimates that 877,643 people lived in Montgomery County on July 1, 2025. That ranks #71 of 3,222 county equivalents nationally and #3 of 67 in Pennsylvania. Since the April 1, 2020 estimates base of 856,392, the population has grown by 21,251 (+2.5%), compared with +0.4% for Pennsylvania as a whole.

With 482.9 square miles of land, that is 1,817 people per square mile (702 per km²), placing Montgomery County #90 nationally for density and #3 in Pennsylvania. The median county equivalent has 47 people per square mile; the Pennsylvania median is 137. Put another way, there are about 0.352 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 Montgomery County

Montgomery County is divided into 62 municipalities and townships. In Pennsylvania, county subdivisions are local governments, and together they cover all of the county’s land and residents.

The most populous is Lower Merion township, with 64,691 residents (7.4% of the county), and it is also the largest by land at 23.6 mi². The county seat, Norristown borough, has 35,911 residents. Among those with at least 1,000 residents in 2020, Bridgeport borough grew fastest since then (+14.8%).

Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each subdivision inside Montgomery County. Land: 2026 Census Gazetteer. How communities are listed.

Metropolitan area

Montgomery County is a central county of the Philadelphia-Camden-Wilmington, PA-NJ-DE-MD Metropolitan Statistical Area, in the Montgomery County-Bucks County-Chester County, PA metropolitan division. Its 11 county equivalents have 6,329,118 residents on 4,603.2 square miles of land; Montgomery County accounts for 10.5% of the land and 13.9% of the residents. By combined land it ranks #58 of 393 metropolitan areas, and #9 by population. It belongs to the Philadelphia-Reading-Camden, PA-NJ-DE-MD Combined Statistical Area.

ZIP codes

71 ZIP Code Tabulation Areas have land in Montgomery County; 58 of them have most of their land inside the county, and the others mainly cover neighboring areas.

1804118054180701807318074180761891418915189361896418969190011900219003190041900619009190101901219025190271903119034190351903819040190411904419046190661907219075190831908519087190901909519096191181912819401194031940519406194221942619428194351943619437194381944019444194461945319454194561946019462194641946819472194731947419477194901949219504195051951219525

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 Montgomery County

Montgomery County shares a land border with 6 county equivalents. It has more land than 3 of them. The largest neighbor is Berks County (856.4 mi²) and the smallest is Philadelphia County (134.3 mi²). Together with its neighbors, Montgomery County forms a block of 3,357.8 mi² of land, of which it holds 14.4%.

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

Montgomery County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 2.1 times as much. Pennsylvania’s county land could hold about 93 areas the size of Montgomery County.

Another way to picture it: the same land area would fill a square about 22 miles (35.4 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 Montgomery County?

Montgomery County has more land than 1,078 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 Montgomery County at #2,224 nationally by total area, 80 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 0.9%, compared with a national county-equivalent median of 1.2% — 0.3 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 Montgomery 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.