Ontario County, New York

Ontario County, New York
Ontario County Courthouse in Canandaigua, 2014
Location within the U.S. state of New York
Coordinates: 42°51′N 77°17′W / 42.85°N 77.29°W / 42.85; -77.29
Country United States
State New York
Founded1789
Named afterLake Ontario
SeatCanandaigua
Largest cityGeneva
Area
 • Total
663 sq mi (1,720 km2)
 • Land644 sq mi (1,670 km2)
 • Water18 sq mi (47 km2)  2.8%
Population
 (2020)
 • Total
112,458
 • Density169/sq mi (65/km2)
Time zoneUTC−5 (Eastern)
 • Summer (DST)UTC−4 (EDT)
Congressional districts24th, 25th
Websitewww.ontariocountyny.gov

Ontario County is a county in the U.S. state of New York. As of the 2020 United States census, the population was 112,458. The county seat is Canandaigua. The county is part of the Finger Lakes region of the state.

Ontario County is part of the Rochester, New York metropolitan area.

In 2006, Progressive Farmer rated Ontario County as the "Best Place to Live" in the U.S., for its "great schools, low crime, excellent health care" and its proximity to Rochester.