The collection represents the span of Williams' architectural practice through drawings, photographs and a very small amount of papers. The majority of the collection consists of working drawings for a select number of projects. These projects include the Holmes residence "the Chimneys" on Long Island, the alteration and addition for the Donnell branch of the New York Public Library and the main branch, and the Rutherford Free Public Library. Also included are the New Milford Historical Society and New Milford Public Library as well as the United States Embassy building in Tokyo, Japan as well as other smaller projects. A wide range of projects are represented in presentation drawings, largely color renderings on board. These drawings consist of projects mainly on the East Coast including libraries, commercial work, residential work, schools, memorials, office buildings, a railroad station, a club, a post office, a hospital as well as unidentified projects. Notable projects include the Carstadt Memorial Municipal building, Essex County Country Club, Hackensack Golf Clubhouse, the National Academy of Design and several projects in Rutherford, New Jersey. Studies for executed projects are also included as well as studies are of other architects' work to serve as inspiration to Williams. Some of the Photostats in the collection are reproductions of original drawings. Photographs mainly document the exterior of a building while some interior views are included especially for the Holmes residence. A small amount of large-scale photographs mounted on board for display are also included. Miscellaneous papers are included for the Holmes residence and the New Milford Public Library. Finally, a poster and two notebooks comprised of notes, sketches and calculations for various projects complete the collection.