The majority of the Fire Island National Seashore's museum collections are related to the Floyd Family. However, the are objects and documents related to the United States Life Saving Service, the Fire Island Light Station, the history of Fire Island and its communities and a collection related to the history of the park. The materials that are not on permanent exhibit are housed in the Curatorial Storage Facility for preservation and protection.
The Historic Collection, dating from the late 1600s until the 1970s, contains over 25,000 objects. These include oil on canvas paintings, lithographs, steel engravings, shirts, socks, shoes, rifles, sabers, uniforms, hats, bodices, gloves, books, drawings, silverware, cups, saucers, plates, plates, glasses, bottles, rings, fans, dresses, wagons, blueprints, maps and magazines and many other objects related to the use and occupancy of the Old Mastic House and the property by the Floyd Family.