Seneca County area

Population and density of Seneca County

The Census Bureau estimates that 32,883 people lived in Seneca County on July 1, 2025. That ranks #1,415 of 3,222 county equivalents nationally and #57 of 62 in New York. Since the April 1, 2020 estimates base of 33,824, the population has declined by 941 (−2.8%), compared with −1% for New York as a whole.

With 323.7 square miles of land, that is 102 people per square mile (39 per km²), placing Seneca County #977 nationally for density and #36 in New York. The median county equivalent has 47 people per square mile; the New York median is 112. Put another way, there are about 6.3 acres of land per resident.

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 Seneca County

Seneca County is divided into 11 cities and towns. In New York, county subdivisions are local governments, and together they cover all of the county’s land and residents.

The most populous is Seneca Falls town, with 8,845 residents (26.9% of the county). The largest by land is Fayette town, at 54.8 mi², or 16.9% of the county’s land. The county seat, Waterloo town, has 7,213 residents.

Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each subdivision inside Seneca County. Land: 2026 Census Gazetteer. How communities are listed.

Metropolitan area

Seneca County is a central county of the Seneca Falls, NY Micropolitan Statistical Area. Seneca County is the area’s only county equivalent, so the micro area has the same 323.7 square miles of land. By combined land it ranks #515 of 542 micropolitan areas, and #420 by population. It belongs to the Rochester-Batavia-Seneca Falls, NY Combined Statistical Area.

ZIP codes

15 ZIP Code Tabulation Areas have land in Seneca County; 8 of them have most of their land inside the county, and the others mainly cover neighboring areas.

130651314613148131651443314456144891452114532145411458814841148471486014886

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 Seneca County

Seneca County shares a land border with 6 county equivalents. Each of them has more land than Seneca County. The largest neighbor is Cayuga County (691.6 mi²) and the smallest is Schuyler County (328.3 mi²). Together with its neighbors, Seneca County forms a block of 3,404.3 mi² of land, of which it holds 9.5%.

How big is Seneca County compared with U.S. states?

Seneca County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 3.2 times as much. New York’s county land could hold about 146 areas the size of Seneca County.

Another way to picture it: the same land area would fill a square about 18 miles (29 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 Seneca County?

Seneca County has more land than 469 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 Seneca County at #2,635 nationally by total area, 118 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 17.1%, compared with a national county-equivalent median of 1.2% — 15.9 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 Seneca County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

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.