County outline
Where Las Piedras Municipio is located
Area breakdown
Land accounts for 100% of Las Piedras Municipio’s measured area and water for 0%. Its combined area converts to 87.8 square kilometers or approximately 21,693 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 33.882 | 87.754 | 21,684.5 |
| Water | 0.013 | 0.034 | 8.3 |
| Total | 33.895 | 87.788 | 21,692.8 |
How Las Piedras Municipio compares
By original Census land area, Las Piedras Municipio ranks #51 of 78 in Puerto Rico and #3162 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 0.807 times the Puerto Rico county-equivalent median of 42 square miles. It accounts for 1% of the combined county land area in the state.
See the complete Puerto Rico ranking · What counts as a county equivalent?
Population and density of Las Piedras Municipio
The Census Bureau estimates that 34,723 people lived in Las Piedras Municipio on July 1, 2025. That ranks #1,350 of 3,222 county equivalents nationally and #31 of 78 in Puerto Rico. Since the April 1, 2020 estimates base of 35,178, the population has declined by 455 (−1.3%), compared with −3.1% for Puerto Rico as a whole.
With 33.9 square miles of land, that is 1,025 people per square mile (396 per km²), placing Las Piedras Municipio #183 nationally for density and #27 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 0.624 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 35,172 | 35,111 | 34,753 | 34,672 | 34,798 | 34,723 |
| Change | — | −61 | −358 | −81 | +126 | −75 |
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 Piedras Municipio
Puerto Rico has no incorporated places below the municipio: Las Piedras 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 Piedras Municipio is a central county of the San Juan-Bayamón-Caguas, PR Metropolitan Statistical Area. Its 40 county equivalents have 2,024,195 residents on 1,437.8 square miles of land; Las Piedras Municipio accounts for 2.4% of the land and 1.7% of the residents. By combined land it ranks #229 of 393 metropolitan areas, and #36 by population. It belongs to the San Juan-Bayamón, PR Combined Statistical Area.
ZIP codes
3 ZIP Code Tabulation Areas have land in Las Piedras Municipio; 1 of them have most of their land inside the county, and the others mainly cover neighboring areas.
007710077700791
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 Piedras Municipio
Las Piedras Municipio shares a land border with 7 county equivalents. It has more land than 2 of them. The largest neighbor is Río Grande Municipio (60.6 mi²) and the smallest is Juncos Municipio (26.5 mi²). Together with its neighbors, Las Piedras Municipio forms a block of 358.6 mi² of land, of which it holds 9.4%.
| Bordering county equivalent | Land mi² | Size vs. Las Piedras | Compare |
|---|---|---|---|
| Río Grande Municipio | 60.6 | 1.8× larger | Compare |
| Yabucoa Municipio | 55.2 | 1.6× larger | Compare |
| San Lorenzo Municipio | 53.1 | 1.6× larger | Compare |
| Naguabo Municipio | 51.7 | 1.5× larger | Compare |
| Humacao Municipio | 44.7 | 1.3× larger | Compare |
| Canóvanas Municipio | 32.9 | about the same | Compare |
| Juncos Municipio | 26.5 | 1.3× smaller | Compare |
How big is Las Piedras Municipio compared with U.S. states?
Las Piedras Municipio has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 31 times as much. Puerto Rico’s county land could hold about 101 areas the size of Las Piedras Municipio.
Another way to picture it: the same land area would fill a square about 5.82 miles (9.4 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 Piedras Municipio?
Las Piedras Municipio has more land than 60 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 Piedras Municipio at #3,179 nationally by total area, 17 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%, compared with a national county-equivalent median of 1.2% — 1.1 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 Piedras Municipio in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #3161 | Santa Isabel Municipio, Puerto Rico | 34.1 | Compare |
| #3162 | Las Piedras Municipio, Puerto Rico | 33.9 | This county |
| #3163 | Portsmouth city, Virginia | 33.3 | 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 18.187237, -65.871272. 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: 87,752,911 m²; AWATER: 32,509 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 big is Las Piedras Municipio?
Las Piedras Municipio, Puerto Rico has 33.9 square miles (87.8 km²) of land and 0.013 square miles of water, for a total area of 33.9 square miles. It ranks #3162 of 3,222 U.S. county equivalents by land area.
Is Las Piedras Municipio the largest county in Puerto Rico?
No. Las Piedras Municipio ranks #51 of 78 in Puerto Rico by land area. The largest is Arecibo Municipio, with 126 square miles of land.
What counties border Las Piedras Municipio?
Las Piedras Municipio shares a land border with Juncos Municipio, Humacao Municipio, Naguabo Municipio, Yabucoa Municipio, Canóvanas Municipio, San Lorenzo Municipio, and Río Grande Municipio.
What is the population of Las Piedras Municipio?
The Census Bureau estimates Las Piedras Municipio had 34,723 residents on July 1, 2025, ranking #1,350 of 3,222 county equivalents. That is 1,025 people per square mile of land.
What is the county seat of Las Piedras Municipio?
The county seat of Las Piedras Municipio is Las Piedras.
Is Las Piedras Municipio part of a metropolitan area?
Yes. It is a central county of the San Juan-Bayamón-Caguas, PR Metropolitan Statistical Area, which has 40 county equivalents and 2,024,195 residents.
How many ZIP codes are in Las Piedras Municipio?
3 ZIP Code Tabulation Areas have land in Las Piedras Municipio, and 1 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.
How does Las Piedras Municipio compare with U.S. states?
It has less land than every state. Rhode Island, the smallest, has 30.5 times as much land.
How many acres of land are in Las Piedras Municipio?
The land measurement converts to approximately 21,684 acres. Including water, total area is approximately 21,693 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.