Puerto Rico counties by area

Understanding Puerto Rico’s county areas

The land-area range runs from Cataño Municipio at 4.8 mi² to Arecibo Municipio at 126 mi². The largest has 26.1 times the land area of the smallest and accounts for 3.7% of the combined county land in Puerto Rico. Compare with every state’s largest county.

The median county-equivalent land area is 42 mi², below the national median of 604.5 mi². The median describes the middle of the county size distribution; it does not describe how people or development are distributed. A state with a few very large counties can have a much smaller median than its largest entry suggests.

Where water changes the picture

Vieques Municipio has the most assigned water area, at 213.2 mi². Culebra Municipio has the highest water share, with water making up 93.1% of its total area. Water area and water percentage answer different questions: the first measures an amount, while the second measures the mix of land and water.

Across all 78 entries, water accounts for 35.7% of the combined total area. This is calculated from the summed land and water measurements, rather than averaging county percentages, which would give each small and large county equal weight.

Where people live

An estimated 3,184,835 people lived in Puerto Rico on July 1, 2025 (−3.1% since 2020), or 0.9% of the national total in this dataset. San Juan Municipio is the most populous county equivalent, with 329,737 residents — 10.4% of the state. The largest by land, Arecibo Municipio, has 85,539.

Across the state there are 930 people per square mile of land. County densities range from 6,883 in San Juan Municipio to 118 in Maricao Municipio; the median county equivalent has 754. Switch the map above to density to see where the state’s population concentrates.

Compare the largest and smallest county equivalents in Puerto Rico to see land, water, and total area on the same scale.

These calculations use the 2026 Census county records listed below. County-equivalent boundaries vary between states; area alone does not measure population, density, or usable land. See coverage and calculation rules.