This historic structure report (HSR) is intended to serve a planning document for the Ellis Island Historic Seawall Rehabilitation, and as a resource for the long-term maintenance of the structure. The seawall rehabilitation is a collaborative effort between the U.S. Army Corps of Engineers, New York District (COE); the Denver Service Center (DSC) of the National Park Service (NPS); and the Statue of Liberty National Monument/Ellis Island National Historic Site (STLI/ELIS). This HSR will provide the Corps of Engineers (which has submitted the schematic design for the rehabilitation) and the park with a developmental history and comprehensive description of the structure. Its objective is to aid in design, rehabilitation, and maintenance decisions, so that the seawall's unique structural problems can be addressed while minimizing loss of historic material and alteration of the historic structure.