County outline
Where San Lorenzo Municipio is located
Area breakdown
Land accounts for 99.8% of San Lorenzo Municipio’s measured area and water for 0.2%. Its combined area converts to 137.8 square kilometers or approximately 34,055 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 53.112 | 137.559 | 33,991.7 |
| Water | 0.099 | 0.256 | 63.4 |
| Total | 53.211 | 137.816 | 34,055 |
How San Lorenzo Municipio compares
By original Census land area, San Lorenzo Municipio ranks #22 of 78 in Puerto Rico and #3125 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 1.265 times the Puerto Rico county-equivalent median of 42 square miles. It accounts for 1.6% 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 San Lorenzo Municipio
The Census Bureau estimates that 37,275 people lived in San Lorenzo Municipio on July 1, 2025. That ranks #1,286 of 3,222 county equivalents nationally and #28 of 78 in Puerto Rico. Since the April 1, 2020 estimates base of 37,691, the population has declined by 416 (−1.1%), compared with −3.1% for Puerto Rico as a whole.
With 53.1 square miles of land, that is 702 people per square mile (271 per km²), placing San Lorenzo Municipio #259 nationally for density and #45 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 0.912 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 37,670 | 37,630 | 37,233 | 37,223 | 37,343 | 37,275 |
| Change | — | −40 | −397 | −10 | +120 | −68 |
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 San Lorenzo Municipio
Puerto Rico has no incorporated places below the municipio: San Lorenzo 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
San Lorenzo 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; San Lorenzo Municipio accounts for 3.7% of the land and 1.8% 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
4 ZIP Code Tabulation Areas have land in San Lorenzo Municipio; 1 of them have most of their land inside the county, and the others mainly cover neighboring areas.
00725007540077700778
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 San Lorenzo Municipio
San Lorenzo Municipio shares a land border with 6 county equivalents. It has more land than 4 of them. The largest neighbor is Caguas Municipio (58.6 mi²) and the smallest is Juncos Municipio (26.5 mi²). Together with its neighbors, San Lorenzo Municipio forms a block of 301.8 mi² of land, of which it holds 17.6%.
| Bordering county equivalent | Land mi² | Size vs. San Lorenzo | Compare |
|---|---|---|---|
| Caguas Municipio | 58.6 | 1.1× larger | Compare |
| Yabucoa Municipio | 55.2 | about the same | Compare |
| Patillas Municipio | 46.6 | 1.1× smaller | Compare |
| Las Piedras Municipio | 33.9 | 1.6× smaller | Compare |
| Gurabo Municipio | 27.9 | 1.9× smaller | Compare |
| Juncos Municipio | 26.5 | 2× smaller | Compare |
How big is San Lorenzo Municipio compared with U.S. states?
San Lorenzo 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 64 areas the size of San Lorenzo Municipio.
Another way to picture it: the same land area would fill a square about 7.29 miles (11.7 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 San Lorenzo Municipio?
San Lorenzo Municipio has more land than 97 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 San Lorenzo Municipio at #3,152 nationally by total area, 27 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% — 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 San Lorenzo Municipio in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #3124 | Norfolk city, Virginia | 53.3 | Compare |
| #3125 | San Lorenzo Municipio, Puerto Rico | 53.1 | This county |
| #3126 | Cayey Municipio, Puerto Rico | 51.9 | 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 18.146921, -65.976915. 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: 137,559,503 m²; AWATER: 256,428 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 San Lorenzo Municipio?
San Lorenzo Municipio, Puerto Rico has 53.1 square miles (137.6 km²) of land and 0.099 square miles of water, for a total area of 53.2 square miles. It ranks #3125 of 3,222 U.S. county equivalents by land area.
Is San Lorenzo Municipio the largest county in Puerto Rico?
No. San Lorenzo Municipio ranks #22 of 78 in Puerto Rico by land area. The largest is Arecibo Municipio, with 126 square miles of land.
What counties border San Lorenzo Municipio?
San Lorenzo Municipio shares a land border with Caguas Municipio, Yabucoa Municipio, Juncos Municipio, Patillas Municipio, Gurabo Municipio, and Las Piedras Municipio.
What is the population of San Lorenzo Municipio?
The Census Bureau estimates San Lorenzo Municipio had 37,275 residents on July 1, 2025, ranking #1,286 of 3,222 county equivalents. That is 702 people per square mile of land.
What is the county seat of San Lorenzo Municipio?
The county seat of San Lorenzo Municipio is San Lorenzo.
Is San Lorenzo 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 San Lorenzo Municipio?
4 ZIP Code Tabulation Areas have land in San Lorenzo 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 San Lorenzo Municipio compare with U.S. states?
It has less land than every state. Rhode Island, the smallest, has 19.5 times as much land.
How many acres of land are in San Lorenzo Municipio?
The land measurement converts to approximately 33,992 acres. Including water, total area is approximately 34,055 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.