The Marjorie McGown Collection consists largely of ephemera from San Antonio society and cultural events between 1909 and 1970, including materials related to the American Red Cross during World War I, the 1931 San Antonio Bicentennial, the Junior League, the Order of the Alamo, art exhibits, ballets, musical events, operas, and plays. The majority of the materials are related to events in San Antonio, though there are some programs from Miss McGown's travels, including items from Houston, New York City, London, and Paris. The collection also includes some personal correspondence, two scrapbooks, a pressed fern book, and a sketching purse. Some material is dated from after Miss McGown's death in 1965, and was added to the collection by an unknown individual.

Collection of ephemera related to Encino Press or William D. Wittliff. The archival collection accompanies the library's Beretta-Encino Press Collection, consisting of print copies of a majority of the press's publications and other associated works.

This collection consists of two journals belonging to Mary Catherine Bradley Gillespie. These journals primarily contain poetry written between 1853 and 1889; other entries include notes about sermons, Sunday School lessons, family members, and music. The collection also includes a handwritten transcription by Gillespie's grandson, William Bulford Adamson, and a printed copy of the hardcover book issued by the Trinity University Alumni Association in 1972.

This collection consists of correspondence written or received by members of the Armstrong family and their associates. Some of the manuscripts are incomplete, with pages missing. Included are letters from Mary J. Durst, Mary Helena "Mollie" Durst Armstrong, and D.W.C. Baker. One letter's author is unidentified.

This collection consists of material from Susan Russell Marcus representing her involvement with the Learning About Learning Foundation, the creation of the New World Kids summer arts camp at the Aldrich Contemporary Arts Museum, the New World Kids book series, and interview footage of Paul Baker, as well as other projects she contributed to.

This collection contains material from the former director of public relations, Leon “Tex” Taylor Taylor. The collection includes correspondence, biographical files, development department files, samples of print media, various articles about Trinity University, and assorted event files spanning Taylor’s tenure at Trinity University from 1947 to 1987.

Typescript copy of original manuscript memoirs by John Beldon Billingsley (1830-1904).

Deed for the 1860 transfer of land in DeWitt County, Texas, from Peter and Louise Metz to the Trustees of the Methodist Episcopal Church South.

1899 application by Laura Schaefer of San Antonio, Texas, for membership in the Daughters of the Confederacy.

Program for the 1948 Caldwell County Centennial coronation and pageant.

Three manuscripts related to the 1888 San Antonio International Fair: a timeline of events, an account of the cattle roping contest, and an account of George W. Saunders's renowned steer named Geronimo.

A listing of legal actions in Tehuacana, Texas, from January 20, 1871 to June 26, 1875. Most of the records are for deeds, powers of attorney, and contracts. Trinity University is mentioned as a party in actions scattered throughout the book. A. Berry, secretary of the Board of Trustees, is a participant in many actions. A list of subscriptions to the university is recorded on July 20, 1872.

Photograph of President John F. Kennedy and First Lady Jacqueline Kennedy visiting Kelly Air Force Base in San Antonio on November 21, 1963, the day before his assassination.

Legal document transferring the title for land in Texas (then a part of Mexico) from James Miles, Logan Vandeveer, and Edward Tatum to David Breeding.

Souvenir program for the Cattles Raisers Association of Texas convention held in San Antonio, Texas, March 1901.

Two copies of a 1963-1964 booklet for the South San Antonio chapter of the Order of the Eastern Star.

Collection of circulars, pamphlets, speeches, and other ephemera related to the Wilmot Proviso. The Wilmot Proviso was introduced in the United States House of Representatives on August 8, 1846 by Congressman David Wilmot as a provision of an appropriations bill. The proviso sought to ban slavery in any territory acquired from Mexico as a result of the Mexican-American War. The bill passed in the House but failed in the Senate. Although it did not pass into law, the Wilmot Proviso is credited with intensifying the slavery debate in the years leading up to the Civil War.

Collection of primary source materials related to the 1921 flood in San Antonio, Texas, assembled by historian Dr. Char Miller.