White Plains is a city in Westchester County, New York, United States, and the eleventh-largest city in the state. An outer suburb of New York City, it is the county seat and commercial hub of Westchester, a densely populated suburban county that is home to approximately one million people. White Plains is located in south-central Westchester, with its downtown (Mamaroneck Avenue) 25 miles (40 km) north of Midtown Manhattan.