Yonkers is the ninth-most populous city in the U.S. state of New York and the most-populous city in Westchester County. A centrally located m…Yonkers is the ninth-most populous city in the U.S. state of New York and the most-populous city in Westchester County. A centrally located municipality within the New York metropolitan area, Yonkers had a population of 211,569 at the 2020 United States census. Yonkers is classified as an inner suburb of New York City, immediately north of the Bronx and approximately 2.4 miles north of Marble Hill.