Westchester County is a county in the U.S. state of New York. It is the second-most populous county on the mainland of New York, after the Bronx, and the most populous county in the state north of New York City. According to the 2010 Census, the county had a population of 949,113, estimated to have increased by 3.3% to 980,244 by 2017. Situated in the Hudson Valley, Westchester covers an area of 450 square miles (1,200 km), consisting of six cities, 19 towns, and 23 villages. Established in 1683, Westchester was named after the city of Chester, England. The county seat is the city of White Plains, while the most populous municipality in the county is the city of Yonkers, with an estimated 200,807 residents in 2016.
As of 2010, there were 949,113 residents at an average density of 807 per square mile (312/km²). The racial makeup of the county was 57.4% non-Hispanic White, 15.6% African American, 0.4% Native American, 5.4% Asian, 0.1% Pacific Islander, 7.6% from other races, and 3.2% from two or more races. Hispanic or Latino of any race were 21.8% of the population. 71.7% spoke only English at home, while 14.4% spoke Spanish, 3.5% Italian, 1.1% Portuguese and 1.1% French at home.
There were 337,142 households of which 34% had children under the age of 18 living with them, 53.9% were married couples living together, 12.2% had a female householder with no husband present, and 30.2% were non-families. 25.7% of all households were made up of individuals and 10.3% had someone living alone who was 65 years of age or older. The average household size was 2.67 and the average family size was 3.21.
Age distribution was 25% under the age of 18, 7.2% from 18 to 24, 30.4% from 25 to 44, 23.5% from 45 to 64, and 14% who were 65 years of age or older. The median age was 38 years. For every 100 females, there were 91.70 males. For every 100 females age 18 and over, there were 87.30 males.
According to census data, the per capita income for the county in 1999 was $36,726. The American Community Survey lists Westchester in 2011 with the median household income of $77,006, the 47th highest in the country. The Census Bureau reports that 6.4% of families and 8.7% (2003) of the population were below the poverty line, including 26.53% of those under age 18 and 7.60% of those age 65 or over.
As of 2000, several different expatriate populations lived in Westchester County. Notable French communities are located in Larchmont, Mamaroneck, and New Rochelle, while Scarsdale and Bronxville are the preferred locations for Japanese immigrants.