Rosenhayn is a census-designated place and unincorporated area located within Deerfield Township, in Cumberland County, New Jersey. It is part of the Vineland-Milleville- Bridgeton Primary Metropolitan Statistical Area for statistical purposes. As of the United States 2000 Census, the CDP population was 1,099. Rosenhayn was founded as a Jewish agricultural colony and the 1898 Rosenhayn synagogue is one of fewer than a hundred surviving nineteenth century synagogue buildings in the United States.