Seaside Heights is a borough situated on the Jersey Shore, within Ocean County, in the U.S. state of New Jersey. As of the 2020 United States census, the borough's population was 2,440, a decrease of 447 from the 2010 census count of 2,887, which in turn had reflected a decline of 268 from the 3,155 counted in the 2000 census. Seaside Heights is located on the Barnegat Peninsula, a long, narrow barrier peninsula that separates the Barnegat Bay from the Atlantic Ocean.