Ontario County area

Population and density of Ontario County

The Census Bureau estimates that 113,130 people lived in Ontario County on July 1, 2025. That ranks #572 of 3,222 county equivalents nationally and #25 of 62 in New York. Since the April 1, 2020 estimates base of 112,476, the population has grown by 654 (+0.6%), compared with −1% for New York as a whole.

With 644 square miles of land, that is 176 people per square mile (68 per km²), placing Ontario County #688 nationally for density and #25 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 3.6 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 Ontario County

Ontario County is divided into 18 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 Victor town, with 16,422 residents (14.5% of the county). The largest by land is Phelps town, at 64.9 mi², or 10.1% of the county’s land. The county seat, Canandaigua town, has 11,258 residents. Among those with at least 1,000 residents in 2020, Farmington town grew fastest since then (+6.1%).

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

Metropolitan area

Ontario County is a central county of the Rochester, NY Metropolitan Statistical Area. Its 5 county equivalents have 1,056,149 residents on 2,927.7 square miles of land; Ontario County accounts for 22% of the land and 10.7% of the residents. By combined land it ranks #101 of 393 metropolitan areas, and #55 by population. It belongs to the Rochester-Batavia-Seneca Falls, NY Combined Statistical Area.

ZIP codes

27 ZIP Code Tabulation Areas have land in Ontario County; 19 of them have most of their land inside the county, and the others mainly cover neighboring areas.

144241442514432144531445614463144661446914471144721447514485144871448914504145121451314522145321453414537145441454814560145611456414585

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 Ontario County

Ontario County shares a land border with 6 county equivalents. It has more land than 4 of them. The largest neighbor is Steuben County (1,390.5 mi²) and the smallest is Seneca County (323.7 mi²). Together with its neighbors, Ontario County forms a block of 4,588.9 mi² of land, of which it holds 14%.

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

Ontario County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.6 times as much. New York’s county land could hold about 73 areas the size of Ontario County.

Another way to picture it: the same land area would fill a square about 25.4 miles (40.8 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 Ontario County?

Ontario County has more land than 1,746 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 Ontario County at #1,534 nationally by total area, 58 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 2.8%, compared with a national county-equivalent median of 1.2% — 1.6 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 Ontario 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.