County outline
Where Monmouth County is located
Area breakdown
Land accounts for 70.8% of Monmouth County’s measured area and water for 29.2%. Its combined area converts to 1,713 square kilometers or approximately 423,296 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 468.204 | 1,212.643 | 299,650.6 |
| Water | 193.196 | 500.375 | 123,645.4 |
| Total | 661.4 | 1,713.018 | 423,296 |
How Monmouth County compares
By original Census land area, Monmouth County ranks #6 of 21 in New Jersey and #2199 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 1.454 times the New Jersey county-equivalent median of 322 square miles. It accounts for 6.4% of the combined county land area in the state.
See the complete New Jersey ranking · What counts as a county equivalent?
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.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #2198 | Worcester County, Maryland | 468.3 | Compare |
| #2199 | Monmouth County, New Jersey | 468.2 | This county |
| #2200 | Androscoggin County, Maine | 468 | Compare |
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.
Representative coordinates
The Census internal point is 40.287048, -74.152446. It represents a location inside the geography; it is not necessarily the centroid or the address of a courthouse.
Source and precision
U.S. Census Bureau, 2026 Gazetteer Files, Counties. Original ALAND: 1,212,642,022 m²; AWATER: 500,374,486 m². Rankings use ALAND; exact ties use ascending GEOID. Tables preserve Census-published square miles to three decimals, with conversions based on those values.
Common questions
How many acres of land are in Monmouth County?
The land measurement converts to approximately 299,651 acres. Including water, total area is approximately 423,296 acres. One square mile equals 640 acres.
Why might another source show a different area?
Check whether it reports land or total area, its Census vintage, and its rounding. Our guide explains how to reconcile county area figures.
Can this establish a property boundary?
No. Statistical measurements and generalized maps do not establish property lines. Consult the relevant local surveying or land-records authority.