Cayey Municipio area

Cayey Municipio, Puerto Rico covers 51.9 square miles: 51.9 square miles of land and 0.026 square miles of water. Its county seat is Cayey. An estimated 40,027 people lived there in 2025.

Official Census measurements · GEOID 720352026 Gazetteer · retrieved September 27, 2026
Land area51.9 mi²
Water area0.026 mi²
Population (2025)40,027
People per mi²771

County outline

Generalized outline of Cayey Municipio, Puerto Rico
2025 Census cartographic boundary, fitted to this frame. County maps are not at a common scale. The 2026 area measurements below come from the separate Gazetteer release. Map source and limitations.

Where Cayey Municipio is located

Cayey Municipio highlighted on a map of all U.S. county equivalents. Puerto Rico is repositioned as an inset at the common scale. About the maps

Area breakdown

Land accounts for 99.9% of Cayey Municipio’s measured area and water for 0.1%. Its combined area converts to 134.5 square kilometers or approximately 33,238 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land51.909134.44433,221.8
Water0.0260.06716.6
Total51.935134.51133,238.4

How Cayey Municipio compares

By original Census land area, Cayey Municipio ranks #23 of 78 in Puerto Rico and #3126 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 1.236 times the Puerto Rico county-equivalent median of 42 square miles. It accounts for 1.5% 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 Cayey Municipio

The Census Bureau estimates that 40,027 people lived in Cayey Municipio on July 1, 2025. That ranks #1,212 of 3,222 county equivalents nationally and #20 of 78 in Puerto Rico. Since the April 1, 2020 estimates base of 41,653, the population has declined by 1,626 (−3.9%), compared with −3.1% for Puerto Rico as a whole.

With 51.9 square miles of land, that is 771 people per square mile (298 per km²), placing Cayey Municipio #235 nationally for density and #37 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 0.83 acres of land per resident.

Estimated population, 2020–2025 · line scaled to this county’s own range
July 1202020212022202320242025
Estimate41,58441,29640,75740,48240,34140,027
Change—−288−539−275−141−314

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 Cayey Municipio

Puerto Rico has no incorporated places below the municipio: Cayey 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

Cayey 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; Cayey Municipio accounts for 3.6% of the land and 2% 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 Cayey Municipio; 1 of them have most of their land inside the county, and the others mainly cover neighboring areas.

007360075100784

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 Cayey Municipio

Cayey Municipio shares a land border with 6 county equivalents. It has more land than 3 of them. The largest neighbor is Salinas Municipio (69.4 mi²) and the smallest is Aibonito Municipio (31.3 mi²). Together with its neighbors, Cayey Municipio forms a block of 358.9 mi² of land, of which it holds 14.5%.

Map of Cayey Municipio and the 6 county equivalents that border it Guayama Municipio, Puerto Rico: 65 mi² landCidra Municipio, Puerto Rico: 36 mi² landCaguas Municipio, Puerto Rico: 58.6 mi² landSalinas Municipio, Puerto Rico: 69.4 mi² landAibonito Municipio, Puerto Rico: 31.3 mi² landPatillas Municipio, Puerto Rico: 46.6 mi² land
Cayey Municipio (dark) and its bordering county equivalents. Select a neighbor to open its profile. Drawn from the 2025 Census cartographic boundaries in an equal-area projection. How borders are determined.
Bordering county equivalentLand mi²Size vs. CayeyCompare
Salinas Municipio69.41.3× largerCompare
Guayama Municipio651.3× largerCompare
Caguas Municipio58.61.1× largerCompare
Patillas Municipio46.61.1× smallerCompare
Cidra Municipio361.4× smallerCompare
Aibonito Municipio31.31.7× smallerCompare

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

Cayey Municipio has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 20 times as much. Puerto Rico’s county land could hold about 66 areas the size of Cayey Municipio.

Land area: Cayey Municipio and the closest-sized states
Cayey Municipio51.9 mi²
Rhode Island1,033.9 mi²

Another way to picture it: the same land area would fill a square about 7.20 miles (11.6 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 Cayey Municipio?

Cayey Municipio has more land than 96 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
Cayey Municipio51.9 mi²
Puerto Rico median42 mi²
National median604.5 mi²

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 Cayey Municipio at #3,154 nationally by total area, 28 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 0.1%, 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 Cayey Municipio in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#3125San Lorenzo Municipio, Puerto Rico53.1Compare
#3126Cayey Municipio, Puerto Rico51.9This county
#3127Naguabo Municipio, Puerto Rico51.7Compare

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 18.103624, -66.151671. 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: 134,444,464 m²; AWATER: 68,567 m². Rankings use ALAND; exact ties use ascending GEOID. Tables preserve Census-published square miles to three decimals, with conversions based on those values.

Download the official county source ZIP ↗ · Methodology

Common questions

How big is Cayey Municipio?

Cayey Municipio, Puerto Rico has 51.9 square miles (134.4 km²) of land and 0.026 square miles of water, for a total area of 51.9 square miles. It ranks #3126 of 3,222 U.S. county equivalents by land area.

Is Cayey Municipio the largest county in Puerto Rico?

No. Cayey Municipio ranks #23 of 78 in Puerto Rico by land area. The largest is Arecibo Municipio, with 126 square miles of land.

What counties border Cayey Municipio?

Cayey Municipio shares a land border with Guayama Municipio, Cidra Municipio, Caguas Municipio, Salinas Municipio, Aibonito Municipio, and Patillas Municipio.

What is the population of Cayey Municipio?

The Census Bureau estimates Cayey Municipio had 40,027 residents on July 1, 2025, ranking #1,212 of 3,222 county equivalents. That is 771 people per square mile of land.

What is the county seat of Cayey Municipio?

The county seat of Cayey Municipio is Cayey.

Is Cayey 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 Cayey Municipio?

3 ZIP Code Tabulation Areas have land in Cayey 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 Cayey Municipio compare with U.S. states?

It has less land than every state. Rhode Island, the smallest, has 19.9 times as much land.

How many acres of land are in Cayey Municipio?

The land measurement converts to approximately 33,222 acres. Including water, total area is approximately 33,238 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.

Cite this county

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