Las Marías Municipio area

Population and density of Las Marías Municipio

The Census Bureau estimates that 8,638 people lived in Las Marías Municipio on July 1, 2025. That ranks #2,599 of 3,222 county equivalents nationally and #75 of 78 in Puerto Rico. Since the April 1, 2020 estimates base of 8,867, the population has declined by 229 (−2.6%), compared with −3.1% for Puerto Rico as a whole.

With 46.4 square miles of land, that is 186 people per square mile (72 per km²), placing Las Marías Municipio #664 nationally for density and #75 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 3.4 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 Las Marías Municipio

Puerto Rico has no incorporated places below the municipio: Las Marías 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

Las Marías Municipio is not part of any metropolitan or micropolitan statistical area in the Office of Management and Budget’s July 2023 delineation; 1,306 other county equivalents are also outside one. These areas are built around an urban core of at least 10,000 people plus the counties tied to it by commuting, so counties outside them are generally rural.

ZIP codes

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

006100066900670

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 Las Marías Municipio

Las Marías Municipio shares a land border with 5 county equivalents. It has more land than 2 of them. The largest neighbor is Mayagüez Municipio (77.6 mi²) and the smallest is Maricao Municipio (36.6 mi²). Together with its neighbors, Las Marías Municipio forms a block of 331.8 mi² of land, of which it holds 14%.

How big is Las Marías Municipio compared with U.S. states?

Las Marías Municipio has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 22 times as much. Puerto Rico’s county land could hold about 74 areas the size of Las Marías Municipio.

Another way to picture it: the same land area would fill a square about 6.81 miles (11 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 Las Marías Municipio?

Las Marías Municipio has more land than 86 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 Las Marías Municipio at #3,159 nationally by total area, 23 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 0.2%, compared with a national county-equivalent median of 1.2% — 0.9 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 Las Marías 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.