Union County is a
county in the
U.S. state of
New Jersey. At the 2014 Census, its estimated population was 552,939, an increase of 3.1 rom the
2010 United States Census, when its population was enumerated at 536,499, in turn an increase of 13,958 (2.7%) from the 522,541 enumerated in the
2000 Census and making it the seventh-most populous county in the state, having been surpassed by
Ocean County. It is part of the
New York metropolitan area. Its
county seat is
Elizabeth. The
Bureau of Economic Analysis ranked the county as having the 119th-highest
per capita income of all 3,113 counties in the United States (and the eighth-highest in New Jersey) in 2009. A study by Forbes.com determined that Union County pays the second-highest property taxes of all U.S. counties, based on 2007 data. With a population density of 4,955 people per square mile (water excluded), Union County was the 15th-most densely populated county in America as of the 2010 Census, and third-densest in New Jersey, behind
Hudson County (ranked 6th at 9,754) and
Essex County (ranked 11th at 6,126).