The Hunterdon County Historical Society Deats Memorial Library holds more than 1,500 surname or family files. The files contain research queries, genealogy research notes (including those of Hiram E. Deats), family records, news clippings, and a small number of images. The files do not contain any original manuscripts or photographs. File size ranges from one page to multiple folders of documents. The HCHS Family File collection is supplemented by the collections of three former HCHS genealogists: Ida G. Bellis, Frank E. Burd and Phyllis D’Autrechy. These materials are housed in separate folders but are interfiled with the main collection.