Linden is a city in southeastern Union County, New Jersey, United States. It is part of the New York Metropolitan Area, which is about southwest of Manhattan, and bordering Staten Island, a borough of New York City. As of the 2010 United States Census, the city's population was 40,499, reflecting an increase of 1,105 (+2.8%) from the 39,394 counted in the 2000 Census, which had in turn increased by 2,693 (+7.3%) from the 36,701 counted in the 1990 Census.