Alexander McMillan Welch (1869-1943) was a New York City based architect who practiced independently and as a member of Welch, Smith & Provot. His firm was best known for designing New York City townhouses in the Beaux-Arts style. The collection includes 1,641 architectural drawings, 196 student drawings, 14 student notebooks, 99 loose photographs and 3 photo albums of project photography, project specifications and files, and some professional ephemera.

Architectural plans and renderings of Welch's designs, largely New York City residences, circa 1890s-1920s; specifications; photographs; and brochures advertising buildings at 787 Fifth Ave., 628 Fifth Ave., and 71 and 73 Murray Street, in New York City. Drawings and a sketchbook done by Welch while a student; fourteen notebooks containing Welch's notes from Columbia classes in architecture, 1888-1890; licenses to practice in New York and New Jersey, 1904-1923; a certificate, 1937, and related correspondence relating to Welch's appointment as a U.S. delegate to the fourteenth International Congress of Architects, held in Paris, July 18-25, 1937. A list of U.S. delegates is included. Of note are drawings and papers for the restoration of the Dyckman House, an 18th century farmhouse in upper Manhattan (1910-1917); and the Mrs. Rutherford Stuyvesant Estate in Allamuchy, New Jersey, and the Rutherford Stuyvesant Momument in Tranquility Cemetery, Tranquility, New Jersey, designed by sculptor Daniel Chester French.

Three sketchbooks; the first, 1893-1894, containing sketches from his student years at the Columbia School of Mines, Department of Architecture (he received his degree in 1894); the second, 1894-1896, containing sketches made as a student at the Ecole des Beaux-Arts in Paris; and the third, circa 1896-circa 1905, containing sketches for a variety of projects and designs. Buildings and other structures depicted include the Academy of Music on 14th Street, New York City (a seating plan); Wells Fargo Bank Building, Portland, Oregon, 1910; Reunion Hall, Princeton University, 1902; lantern for the Aetna Building, Hartford, Connecticut; Woodland Street entrance to Kinney Park, Hartford, Connecticut, 1905 (some drawings are by others). Program notes from the classes of Paul Blondel and J. Gaudet at the Ecole des Beaux Arts are included. Also, designs (some done in partnership with Joseph Urban) for proposals for the Metropolitan Opera Company on various sites in New York City, circa 1920s; and designs for shopping and music centers in New York City, to 1936.

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.