Monmouth County area

Population and density of Monmouth County

The Census Bureau estimates that 651,035 people lived in Monmouth County on July 1, 2025. That ranks #110 of 3,222 county equivalents nationally and #6 of 21 in New Jersey. Since the April 1, 2020 estimates base of 643,488, the population has grown by 7,547 (+1.2%), compared with +2.8% for New Jersey as a whole.

With 468.2 square miles of land, that is 1,390 people per square mile (537 per km²), placing Monmouth County #130 nationally for density and #9 in New Jersey. The median county equivalent has 47 people per square mile; the New Jersey median is 1,137. Put another way, there are about 0.46 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 Monmouth County

Monmouth County is divided into 53 municipalities and townships. In New Jersey, county subdivisions are local governments, and together they cover all of the county’s land and residents.

The most populous is Middletown township, with 67,135 residents (10.3% of the county). The largest by land is Howell township, at 60.3 mi², or 12.9% of the county’s land. The county seat, Freehold township, has 36,052 residents. Among those with at least 1,000 residents in 2020, Oceanport borough grew fastest since then (+6.3%).

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

Metropolitan area

Monmouth County is a central county of the New York-Newark-Jersey City, NY-NJ Metropolitan Statistical Area, in the Lakewood-New Brunswick, NJ metropolitan division. Its 22 county equivalents have 20,112,448 residents on 6,139.7 square miles of land; Monmouth County accounts for 7.6% of the land and 3.2% of the residents. By combined land it ranks #34 of 393 metropolitan areas, and #1 by population. It belongs to the New York-Newark, NY-NJ-CT-PA Combined Statistical Area.

ZIP codes

52 ZIP Code Tabulation Areas have land in Monmouth County; 49 of them have most of their land inside the county, and the others mainly cover neighboring areas.

07701077020770307704077110771207716077170771807719077200772107722077230772407726077270772807730077310773207733077340773507737077380773907740077460774707748077500775107753077550775607757077580776007762077640850108510085140853508555086910872008724087300873608750

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 Monmouth County

Monmouth County shares a land border with 4 county equivalents. It has more land than 2 of them. The largest neighbor is Burlington County (799.3 mi²) and the smallest is Mercer County (224.5 mi²). Together with its neighbors, Monmouth County forms a block of 2,429.6 mi² of land, of which it holds 19.3%.

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

Monmouth County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 2.2 times as much. New Jersey’s county land could hold about 16 areas the size of Monmouth County.

Another way to picture it: the same land area would fill a square about 21.6 miles (34.8 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 Monmouth County?

Monmouth County has more land than 1,023 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 Monmouth County at #1,535 nationally by total area, 664 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 29.2%, compared with a national county-equivalent median of 1.2% — 28 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 Monmouth 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.