Westchester County is a county located in the southeastern portion of the U.S. state of New York, bordering the Long Island Sound to its east and the Hudson River on its west. The county is the seventh most populous county in the State of New York and the most populous north of New York City. According to the 2020 United States Census, the county had a population of 1,004,456, its highest decennial count ever and an increase of 55,344 from the 949,113 counted in 2010.