Resident Population in Suffolk County, NY was 1535.90900 Thous. of Persons in January of 2024, according to the United States Federal Reserve. Historically, Resident Population in Suffolk County, NY reached a record high of 1535.90900 in January of 2024 and a record low of 1127.03000 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Suffolk County, NY - last updated from the United States Federal Reserve on September of 2025.