The papers of Hugh Lenox Scott (1853-1934) span the years 1582-1981, with the bulk of the items concentrated in the period 1845-1934. The collection consists of correspondence, memoranda, diaries, account books, memoirs, articles, books, speeches, biographical and genealogical material, reports, notes, lists, financial records, maps, photographs, drawings, prints, greeting and calling cards, index cards, printed matter, and other material covering Scott's military service following his graduation from the United States Military Academy in 1876 to his retirement from the army after World War I. It also documents his service as a member of the Board of Indian Commissioners from 1919 to 1933 and his role as chairman of the State Highway Commission of New Jersey during the 1920s.

Significant events and topics covered in the collection include the Indian wars in the late 19th century, especially expeditions against the Sioux and Nez Percé; Indian culture, rights, affairs, and religion, including the Ghost Dance of the Plains Indians; language, in particular sign language; the arrival of Geronimo's band of Chiricahua Apaches at Fort Sill, Oklahoma, and their eventual reparation to the Mescalaro Apache Indian Reservation in New Mexico. Other material within these papers relates to the administration of the United States Office of Indian Affairs Kiowa Agency, Troop L; 7th Calvary, United States Army; and negotiations with the Hopi, Navajo, and Paiute tribes.

Other topics and events include Scott's appointment and work at the Smithsonian Institution's Bureau of Ethnology, the Spanish-American War, and the administration of the military government in Cuba. Scott's service in the Philippines, in particular on Jolo and Sulu Islands, and the campaigns against the Moros; his appointment and tenure as superintendent of the United States Military Academy in West Point, New York; his negotiations with Francisco “Pancho” Villa and the punitive expedition to Mexico in 1916 are chronicled, as well as the preparation and engagement of the United States Army in World War I and Scott's role as chief of staff of the army and his participation in the United States Special Diplomatic Mission to Russia of 1917.

The collection is divided into twelve series, many of which complement one another. The Family Papers series includes early family documents and correspondence, primarily from Scott to his wife Mary Merrill Scott, and provides accounts of Scott's life at various military outposts. The General Correspondence includes incoming and outgoing correspondence and related material covering all aspects of Scott's career and interests.

The Indian Affairs series includes incoming and outgoing correspondence and other material relating to Scott's interests in Native American culture, rights, languages, and affairs. The Official File includes letters received and other material from Scott's military service in Cuba and the Philippines. Included is a letter to Scott's wife providing a description of how Scott was wounded while escorting the prisoner Panglima Hassan. The New Jersey Highway Commission series includes reports and letters sent and received highlighting Scott's central role on the commission.

The Mary Merrill Scott File consists primarily of clippings and letters of condolence on her husband's death as well as financial material. The Diaries and Account Books series includes a typescript of William McKendree Scott's journal of 1845 and Hugh Lenox Scott's diaries and account books, 1881-1934. The Subject File consists primarily of military papers, financial records, including accounts from Fort Sill, genealogical material, and papers relating to American Indians, such as an alphabetical dictionary of the sign language of the Plains Indians. The Writings series consists primarily of speeches, drafts of memoirs and other biographical material, and drafts of articles by Scott. The Printed Matter and Miscellany series consist chiefly of clippings, pamphlets, invitations, calling and membership cards, masonic material, maps, photographs, and other miscellaneous material.

An Addition consists chiefly of drafts of Scott's memoir, and research material related to his writing. A photocopied article and genealogical material are also included.

Correspondents include Tasker Howard Bliss, John J. Pershing, Pancho Villa, Woodrow Wilson, and Leonard Wood.