Series I contains publications authored by Horner and includes Horner's annotated copy of Oregon: Her History, Her Great Men, Her Literature (1919), individual lecture texts for A Vacation on the Mediterranean (1906 and 1907), a typescript copy of "History of Oregon State College, 1865-1907," a typescript of Horner's autobiography (1926), Outlines for Study of Oregon History (ca. 1927), and Days and Deeds in the Oregon Country, 1929. Series II consists of 2 volumes of maps of Europe drawn by Horner's history students in 1902 and 1905. Series III is a collection of pioneer stories written by school children around 1918. Series IV consists of letters of condolence written to Mrs. Horner after John B. Horner's death in 1933.
Series V contains a variety of programs, announcements, invitations, diplomas, and other ephemera. Included are booklets pertaining to the Cauthorn Hall and Alpha Hall dormitories, which the Horners were in charge of early in the 1900s; OAC commencement programs and invitations; a program to the memorial service held for B. L. Arnold on June 29, 1892; programs pertaining to musical, dramatic and literary productions and church, Masonic and educational organizations; and Horner's diplomas from Willamette University.
Series VI consists of three letters written by Horner. Series VII includes six photographic prints of Horner, J. R. N. Bell, and others in Egypt.