Isabela Municipio area

Population and density of Isabela Municipio

The Census Bureau estimates that 42,938 people lived in Isabela Municipio on July 1, 2025. That ranks #1,154 of 3,222 county equivalents nationally and #18 of 78 in Puerto Rico. Since the April 1, 2020 estimates base of 42,944, the population has declined by 6 (−0%), compared with −3.1% for Puerto Rico as a whole.

With 55.3 square miles of land, that is 777 people per square mile (300 per km²), placing Isabela Municipio #234 nationally for density and #36 in Puerto Rico. The median county equivalent has 47 people per square mile; the Puerto Rico median is 754. Put another way, there are about 0.824 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 Isabela Municipio

Puerto Rico has no incorporated places below the municipio: Isabela Municipio is itself the local government. The Census Bureau describes the settlements inside it, such as zonas urbanas and comunidades, as statistical places, and publishes no separate annual estimates for them.

Metropolitan area

Isabela Municipio is a central county of the Aguadilla, PR Metropolitan Statistical Area. Its 7 county equivalents have 250,088 residents on 297.1 square miles of land; Isabela Municipio accounts for 18.6% of the land and 17.2% of the residents. By combined land it ranks #387 of 393 metropolitan areas, and #199 by population. It belongs to the Mayagüez-Aguadilla, PR Combined Statistical Area.

ZIP codes

3 ZIP Code Tabulation Areas have land in Isabela Municipio; 1 of them have most of their land inside the county, and the others mainly cover neighboring areas.

006620067800685

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 Isabela Municipio

Isabela Municipio shares a land border with 4 county equivalents. It has more land than 3 of them. The largest neighbor is San Sebastián Municipio (70.5 mi²) and the smallest is Quebradillas Municipio (22.7 mi²). Together with its neighbors, Isabela Municipio forms a block of 235.3 mi² of land, of which it holds 23.5%.

How big is Isabela Municipio compared with U.S. states?

Isabela Municipio has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 19 times as much. Puerto Rico’s county land could hold about 62 areas the size of Isabela Municipio.

Another way to picture it: the same land area would fill a square about 7.43 miles (12 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 Isabela Municipio?

Isabela Municipio has more land than 101 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 Isabela Municipio at #3,115 nationally by total area, 6 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 39.8%, compared with a national county-equivalent median of 1.2% — 38.6 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 Isabela Municipio 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.