County outline
Where Cidra Municipio is located
Area breakdown
Land accounts for 98.8% of Cidra Municipio’s measured area and water for 1.2%. Its combined area converts to 94.4 square kilometers or approximately 23,325 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 35.994 | 93.224 | 23,036.2 |
| Water | 0.451 | 1.168 | 288.6 |
| Total | 36.445 | 94.392 | 23,324.8 |
How Cidra Municipio compares
By original Census land area, Cidra Municipio ranks #47 of 78 in Puerto Rico and #3158 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 0.857 times the Puerto Rico county-equivalent median of 42 square miles. It accounts for 1.1% 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 Cidra Municipio
The Census Bureau estimates that 39,669 people lived in Cidra Municipio on July 1, 2025. That ranks #1,219 of 3,222 county equivalents nationally and #22 of 78 in Puerto Rico. Since the April 1, 2020 estimates base of 39,973, the population has declined by 304 (−0.8%), compared with −3.1% for Puerto Rico as a whole.
With 36 square miles of land, that is 1,102 people per square mile (426 per km²), placing Cidra Municipio #170 nationally for density and #22 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 0.581 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 39,984 | 39,976 | 39,604 | 39,561 | 39,689 | 39,669 |
| Change | — | −8 | −372 | −43 | +128 | −20 |
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 Cidra Municipio
Puerto Rico has no incorporated places below the municipio: Cidra 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
Cidra 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; Cidra Municipio accounts for 2.5% 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 Cidra Municipio; 1 of them have most of their land inside the county, and the others mainly cover neighboring areas.
007030073600739
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 Cidra Municipio
Cidra 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 Comerío Municipio (28.4 mi²). Together with its neighbors, Cidra Municipio forms a block of 270.6 mi² of land, of which it holds 13.3%.
| Bordering county equivalent | Land mi² | Size vs. Cidra | Compare |
|---|---|---|---|
| Caguas Municipio | 58.6 | 1.6× larger | Compare |
| Cayey Municipio | 51.9 | 1.4× larger | Compare |
| Barranquitas Municipio | 34.2 | 1.1× smaller | Compare |
| Aibonito Municipio | 31.3 | 1.2× smaller | Compare |
| Aguas Buenas Municipio | 30.1 | 1.2× smaller | Compare |
| Comerío Municipio | 28.4 | 1.3× smaller | Compare |
How big is Cidra Municipio compared with U.S. states?
Cidra Municipio has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 29 times as much. Puerto Rico’s county land could hold about 95 areas the size of Cidra Municipio.
Another way to picture it: the same land area would fill a square about 6.00 miles (9.7 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 Cidra Municipio?
Cidra Municipio has more land than 64 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 Cidra Municipio at #3,174 nationally by total area, 16 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 1.2%, compared with a national county-equivalent median of 1.2%. The two percentages are within 0.1 percentage points of each other. 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 Cidra Municipio in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #3157 | Sabana Grande Municipio, Puerto Rico | 36.3 | Compare |
| #3158 | Cidra Municipio, Puerto Rico | 36 | This county |
| #3159 | Villalba Municipio, Puerto Rico | 35.6 | 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 18.174405, -66.161568. 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: 93,224,737 m²; AWATER: 1,167,996 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 Cidra Municipio?
Cidra Municipio, Puerto Rico has 36 square miles (93.2 km²) of land and 0.451 square miles of water, for a total area of 36.4 square miles. It ranks #3158 of 3,222 U.S. county equivalents by land area.
Is Cidra Municipio the largest county in Puerto Rico?
No. Cidra Municipio ranks #47 of 78 in Puerto Rico by land area. The largest is Arecibo Municipio, with 126 square miles of land.
What counties border Cidra Municipio?
Cidra Municipio shares a land border with Cayey Municipio, Comerío Municipio, Aguas Buenas Municipio, Aibonito Municipio, Caguas Municipio, and Barranquitas Municipio.
What is the population of Cidra Municipio?
The Census Bureau estimates Cidra Municipio had 39,669 residents on July 1, 2025, ranking #1,219 of 3,222 county equivalents. That is 1,102 people per square mile of land.
What is the county seat of Cidra Municipio?
The county seat of Cidra Municipio is Cidra.
Is Cidra 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 Cidra Municipio?
3 ZIP Code Tabulation Areas have land in Cidra 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 Cidra Municipio compare with U.S. states?
It has less land than every state. Rhode Island, the smallest, has 28.7 times as much land.
How many acres of land are in Cidra Municipio?
The land measurement converts to approximately 23,036 acres. Including water, total area is approximately 23,325 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.