Roosevelt Island is an island in New York City's East River, within the borough of Manhattan. It lies between Manhattan Island to the west, and the borough of Queens, on Long Island, to the east. It is about 2 miles long, with an area of 147 acres, and had a population of 11,722 as of the 2020 United States census. It consists of two largely residential com…Roosevelt Island is an island in New York City's East River, within the borough of Manhattan. It lies between Manhattan Island to the west, and the borough of Queens, on Long Island, to the east. It is about 2 miles long, with an area of 147 acres, and had a population of 11,722 as of the 2020 United States census. It consists of two largely residential communities: Northtown and Southtown. Roosevelt Island is owned by the city but was leased to the New York State Urban Development Corporation for 99 years in 1969.