Seaside Heights is a borough in Ocean County, New Jersey, United States. As of the 2010 United States Census, the borough's population was 2,887, reflecting a decline of 268 (-8.5%) from the 3,155 counted in the 2000 Census, which had in turn increased by 789 (+33.3%) from the 2,366 counted in the 1990 Census. Seaside Heights is situated on the Barnegat Peninsula, a long, narrow barrier peninsula that separates Barnegat Bay from the Atlantic Ocean. During the summer, the borough attracts a crowd largely under the age of , drawn to a community with boardwalk entertainment and one of the few shore communities with sizable numbers of apartments, attracting as many as 65,000 people who are often out until early morning visiting bars and restaurants.
Seaside Heights was incorporated as a borough by an act of the New Jersey Legislature on February 26, 1913, from portions of both Berkeley Township and Dover Township (now Toms River Township), based on the results of a referendum held on March 25, 1913. The borough was named for its location on the Atlantic Ocean.