Resident Population in Seneca County, NY was 32.34900 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Seneca County, NY reached a record high of 35.40000 in January of 1971 and a record low of 32.34900 in January of 2023. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Seneca County, NY - last updated from the United States Federal Reserve on May of 2024.