This series consists of a variety of materials related to the administrative duties of the Washington Memorial Arch Committee. Materials include agreements and contracts between McKim, Mead & White and builders and sculptors, form letters sent to potential subscribers requesting donations, minutes, proposals, petitions, and reports.

This series includes the correspondence of William R. Stewart and other associates relating to matters concerning the committee, Arch, and subscriptions. The incoming correspondence to Stewart has been arranged alphabetically by the sender's last name. In general, the incoming correspondence to Stewart pertains to subscriptions collected and paid, input on the manuscript for the publication The History of the Washington Arch, and decisions made with the Department of Public Parks. One folder of correspondence from Richard Gilder, the Secretary of the committee, mainly deals with administrative matters such as meetings, resolutions, subscriptions paid, inquiries, costs of supplies, and contracts with particular builders and craftsmen. Stewart's professional involvement with Stanford White is well documented in their correspondence. The three folders of correspondence from Stanford White detail aspects of the construction including differences with the Department of Public Parks, estimates of costs, measurements, models of the eagles, the scaffolding, and the cleaning of the piers.

The outgoing correspondence from Stewart is bound in four letterpress books that are organized chronologically. Indices in the front of the books list correspondents alphabetically along with the page numbers of their letters. The correspondence solicits and thanks participants for subscriptions to the Memorial Arch Fund and details the business of the committee. Other correspondence in the collection includes letters to Thomas Keating from Richard Gilder as well as incoming correspondence to Richard Gilder, Henry G. Marquand, and Stanford White.

Financial materials relating to the fundraising activities for the building of the Arch and, later, the statues of George Washington comprise this subseries.

This series includes plans, memorabilia and photographs from ceremonies involving the Washington Arch. The memorabilia consists of programs and invitations, and the ceremonies include the Centennial Celebration parade, the Laying of the Cornerstone ceremony, and the Dedication ceremony. The photographs of the dedication ceremony and parade are albumens, larger than cabinet size. The plans of the Arch dedication ceremony are oversize.

This series contains photographs and prints that portray the Arch and its sculptures of George Washington. The prints of Arch depict the temporary Arch as well as the completed, permanent Arch. The photographs of the sculptures include close-ups as well as far away shots that show their placement on the east and west ends of the Arch. The photographs were produced by the silver gelatin process and printed on mat paper.

This series contains the draft and published version of The History of the Washington Arch, a narrative text that tells the story of the Arch's beginnings, its main organizers, and the dedication ceremonies that followed. It also contains a 1892 Guide to New York Citythat includes a drawing and description of the Arch.

This series consists of a variety of articles documenting the Washington Arch, its dedication, and sculptures. Included in this series are clippings from The New York Times, Harper's Weekly, The Star, New York Herald, The Tribune, The Press, and The World. In addition, three copies of The Chimney-Seat, an illustrated paper that donated the proceeds from its first two issues to the Washington Memorial Arch Fund, are included.

This series includes materials relating to the personal life of William R. Stewart. Such materials include agreements from his career as an estates manager, bulletins and programs from Grace Church and the Western New York Institution for Deaf Mutes, inventories of estates, and invitations to art openings, weddings, and dances.