Sketchbooks, 1895-1903; sketches, 1894-1896, made while Magonigle was travelling in Europe on Rotch Travelling Scholarship; graphic designs, 1902-1919; rendered competition drawings for government buildings, circa 1907-1920, and memorial structures, circa 1910-1930; photographs of Magonigle's architectural drawings, memorial structures, monuments, and other architectural work, much of it located in New York City, circa 1900s-1930s. Among projects represented in the collection are the Gates Avenue Courthouse, Brooklyn, N.Y.; the Firemen's Memorial, the Robert Fulller Memorial, and the National Watergate Memorial in New York City's Riverside Park; the Liberty Memorial in Kansas City, Mo.; the Isaac Guggenheim house in Port Washington, N.Y.; numerous additions and alterations for the Franklin Murphy mansion in Mendham, N.J.; and the United States Embassy compound in Tokyo, Japan. Also, drawings by other architects including Hugh Ferriss, Thomas Rogers Kimball, Hubert George Ripley, and I.W. Taber, that were presented to Magonigle. Also included are drawings, circa 1910s-1940s, by Magonigle's wife, painter and designer Edith Marion Day; photographs of Day and Magonigle; manuscripts of lectures, literary works, and other writings by Magonigle; and ephemera.

Harold Van Buren Magonigle was a New York-based architect, graphic designer, painter and sculptor. Magonigle married artist Edith Marion Day in 1900. Edith Magonigle was a painter and muralist who served as President of the Society of Women Painters and Sculptors. Edith was a primary collaborator of Harold Van Buren Magonigle in both the decoration and creation of buildings designed by his practice. He was widely known as an architect of memorial structures including the Firemen's Memorial on Riverside Drive and the Liberty Memorial in Kansas City. Other prominent commissions include the Isaac Guggenheim house in Port Washington, New York and the United States Embassy in Tokyo, Japan.

Also, a variety of professional and personal miscellany, such as correspondence, clippings, pamphlets, flyers, postcards, invitations, menus, receipts, a diploma, caricatures of colleagues, and Sawyer's monocle