County outline
Where Barnstable County is located
Area breakdown
Land accounts for 30.2% of Barnstable County’s measured area and water for 69.8%. Its combined area converts to 3,381.3 square kilometers or approximately 835,546 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 394.185 | 1,020.934 | 252,278.4 |
| Water | 911.356 | 2,360.401 | 583,267.8 |
| Total | 1,305.541 | 3,381.336 | 835,546.2 |
How Barnstable County compares
By original Census land area, Barnstable County ranks #11 of 14 in Massachusetts and #2555 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 0.73 times the Massachusetts county-equivalent median of 540.2 square miles. It accounts for 5.1% of the combined county land area in the state.
See the complete Massachusetts ranking · What counts as a county equivalent?
Population and density of Barnstable County
The Census Bureau estimates that 233,539 people lived in Barnstable County on July 1, 2025. That ranks #310 of 3,222 county equivalents nationally and #9 of 14 in Massachusetts. Since the April 1, 2020 estimates base of 229,064, the population has grown by 4,475 (+2%), compared with +1.7% for Massachusetts as a whole.
With 394.2 square miles of land, that is 592 people per square mile (229 per km²), placing Barnstable County #296 nationally for density and #8 in Massachusetts. The median county equivalent has 47 people per square mile; the Massachusetts median is 673. Put another way, there are about 1.1 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 228,055 | 232,449 | 232,970 | 233,592 | 233,951 | 233,539 |
| Change | — | +4,394 | +521 | +622 | +359 | −412 |
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 Barnstable County
Barnstable County is divided into 15 cities and towns. In Massachusetts, county subdivisions are local governments, and together they cover all of the county’s land and residents.
The most populous is Barnstable Town city, with 50,101 residents (21.5% of the county), and it is also the largest by land at 59.9 mi². Among those with at least 1,000 residents in 2020, Wellfleet town grew fastest since then (+4%).
| County subdivision | Population 2025 | Since 2020 | Land mi² | Share of county land |
|---|---|---|---|---|
| Barnstable Town city | 50,101 | +2.5% | 59.9 | 15.2% |
| Falmouth town | 33,361 | +2.5% | 44.1 | 11.2% |
| Yarmouth town | 25,225 | +0.8% | 24.2 | 6.1% |
| Bourne town | 20,772 | +1.2% | 40.7 | 10.3% |
| Sandwich town | 20,575 | +1.5% | 42.9 | 10.9% |
| Mashpee town | 15,468 | +2.8% | 23.4 | 5.9% |
| Dennis town | 14,906 | +1.5% | 20.6 | 5.2% |
| Harwich town | 13,635 | +1.5% | 20.9 | 5.3% |
| Brewster town | 10,457 | +1.3% | 22.9 | 5.8% |
| Chatham town | 6,752 | +2.3% | 16.2 | 4.1% |
| Orleans town | 6,524 | +3.3% | 14.2 | 3.6% |
| Eastham town | 5,844 | +1.6% | 14 | 3.5% |
| Provincetown town | 3,729 | +1.9% | 9.684 | 2.5% |
| Wellfleet town | 3,707 | +4% | 19.8 | 5% |
| Truro town | 2,483 | +2.1% | 21 | 5.3% |
Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each subdivision inside Barnstable County. Land: 2026 Census Gazetteer. How communities are listed.
Metropolitan area
Barnstable County is a central county of the Barnstable Town, MA Metropolitan Statistical Area. Barnstable County is the area’s only county equivalent, so the metro area has the same 394.2 square miles of land. By combined land it ranks #379 of 393 metropolitan areas, and #208 by population. It belongs to the Boston-Worcester-Providence, MA-RI-NH Combined Statistical Area.
ZIP codes
48 ZIP Code Tabulation Areas have land in Barnstable County; 47 of them have most of their land inside the county, and the others mainly cover neighboring areas.
025320253402536025370254002542025430255302556025590256102562025630260102630026310263202633026350263702638026390264102642026430264402645026460264702648026490265002652026530265502657026590266002663026640266602667026680267002671026720267302675
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 Barnstable County
Barnstable County shares a land border with 1 county equivalent. Plymouth County has 1.7 times its land area.
| Bordering county equivalent | Land mi² | Size vs. Barnstable | Compare |
|---|---|---|---|
| Plymouth County | 658.5 | 1.7× larger | Compare |
How big is Barnstable County compared with U.S. states?
Barnstable County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 2.6 times as much. Massachusetts’s county land could hold about 20 areas the size of Barnstable County.
Another way to picture it: the same land area would fill a square about 19.9 miles (32 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 Barnstable County?
Barnstable County has more land than 667 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 Barnstable County at #527 nationally by total area, 2,028 places closer to the top than its land rank. The water assigned to this geography moves it ahead of some county equivalents with more land.
Its water share is 69.8%, compared with a national county-equivalent median of 1.2% — 68.6 percentage points higher. 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 Barnstable County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #2554 | Benton County, Tennessee | 394.3 | Compare |
| #2555 | Barnstable County, Massachusetts | 394.2 | This county |
| #2556 | Jones County, Georgia | 393.9 | 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 41.706123, -70.164823. 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: 1,020,933,632 m²; AWATER: 2,360,402,331 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 Barnstable County?
Barnstable County, Massachusetts has 394.2 square miles (1,020.9 km²) of land and 911.4 square miles of water, for a total area of 1,305.5 square miles. It ranks #2555 of 3,222 U.S. county equivalents by land area.
Is Barnstable County the largest county in Massachusetts?
No. Barnstable County ranks #11 of 14 in Massachusetts by land area. The largest is Worcester County, with 1,510.7 square miles of land.
What counties border Barnstable County?
Barnstable County shares a land border with Plymouth County.
What is the population of Barnstable County?
The Census Bureau estimates Barnstable County had 233,539 residents on July 1, 2025, ranking #310 of 3,222 county equivalents. That is 592 people per square mile of land.
What is the county seat of Barnstable County?
The county seat of Barnstable County is Barnstable.
What cities and towns are in Barnstable County?
Barnstable County has 15 county subdivisions (cities, towns and townships). The most populous five are Barnstable Town city, Falmouth town, Yarmouth town, Bourne town, and Sandwich town.
Is Barnstable County part of a metropolitan area?
Yes. It is a central county of the Barnstable Town, MA Metropolitan Statistical Area.
How many ZIP codes are in Barnstable County?
48 ZIP Code Tabulation Areas have land in Barnstable County, and 47 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.
How does Barnstable County compare with U.S. states?
It has less land than every state. Rhode Island, the smallest, has 2.6 times as much land.
How many acres of land are in Barnstable County?
The land measurement converts to approximately 252,278 acres. Including water, total area is approximately 835,546 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.