ONTARIO COUNTY, situated toward the west part of New York, with Seneca lake on the east, and Canandaigua lake in the south. Area, 617 square miles. Face of the country uneven; soil fertile and well cultivated. Seat of justice, Canandaigua. Pop. in 1810, 42,032; in 1820, 35,312; in 1830, 40,167; in 1840, 43,500; in 1850, 43,925. (Fanning's, 1853)