Union Square is a historic intersection and surrounding neighborhood in Manhattan, New York City, located where Broadway and the former Bowery Road – now Fourth Avenue – came together in the early 19th century. Its name denotes that "here was the union of the two principal thoroughfares of the island". The current Union Square Park is bounded by 14th Street on the south, 17th Street on the north, and Union Square West and Union Square East to the west and east respectively. 17th Street links together Broadway and Park Avenue South on the north end of the park, while Union Square East connects Park Avenue South to Fourth Avenue and the continuation of Broadway on the park's south side. The park is under the aegis of the New York City Department of Parks and Recreation.

Adjacent neighborhoods are the Flatiron District to the north, Chelsea to the west, Greenwich Village to the southwest, East Village to the southeast, and Gramercy Park to the east.

Union Square is part of Manhattan Community District 5 and its primary ZIP Code is 10003. It is patrolled by the 13th Precinct of the New York City Police Department.