Supplementing his collection of printed Western Americana, these papers comprise manuscripts, correspondence, documents, photographs, and miscellanea relating to Rollins's interest and involvement in the American West. Included are typed manuscripts-of articles, stories, and a poem, including some variant copies and revisions; of Gone Haywire (1930), his fictionalized autobiography; and of The Journey and Travelling Memoranda of Robert Stuart . . ., edited by Rollins and published in 1935 as The Discovery of the Oregon Trail: Robert Stuart's Narratives. Correspondence of Rollins (Princeton Class of 1889), of his wife, Beulah, and of her assistant, Elizabeth Shields, consists primarily of responses from libraries, historical societies, and other sources in connection with his research and collecting.

In addition, there are papers of others, including transcripts of 19th-century journals, an autograph manuscript of a diary of an overland trip, and letters from goldminers to their families giving vivid narratives of their experiences; approximately 840 silver gelatin and albumen photographs and postcards (including one photograph album), either taken or collected by Rollins, depicting rodeos, Western towns, gold prospecting, fauna, cattle ranching, and frontier life and travel in such states as Colorado, Arizona, Wyoming, etc. and including images by R.R. Doubleday, J.E. Stimson, W.S. Bowman, and Major Lee Moorhouse; printed material and miscellaneous clippings; and memorabilia/objects, including a lariat and spurs.

The following standard abbreviations, or their variations, are used to identify materials in this collection: Ms = manuscript, AMsS = autograph manuscript signed.