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

Monroe County is a county in the U.S. state of New York, located along Lake Ontario's southern shore. As of 2022, the population was 752,035, according to Census Bureau estimates. Its county seat and largest city is Rochester. The county is named after James Monroe, the fifth president of the United States. Monroe County is part of the Rochester, NY Metropolitan Statistical Area. The county is part of the Finger Lakes region of the state.