Stone Harbor is a borough in Cape May County, in the U.S. state of New Jersey. The borough, and all of Cape May County, is part of the South Jersey region of the state and of the Ocean City metropolitan statistical area, which is part of the Philadelphia-Wilmington-Camden, PA-NJ-DE-MD combined statistical area, also known as the Delaware Valley or Philadelphia metropolitan area. It occupies the southern portion of Seven Mile Island together with its northern neighbor Avalon.