Seaside Park is a
borough in
Ocean County,
New Jersey, United States. As of the
2010 United States Census, the borough's population was 1,579, reflecting a decline of 684 (-30.2%) from the 2,263 counted in the
2000 Census, which had in turn increased by 392 (+21.0%) from the 1,871 counted in the
1990 Census. Seaside Park is situated on the
Barnegat Peninsula, a long, narrow barrier peninsula that separates
Barnegat Bay from the
Atlantic Ocean.