The Southwestern Writers Collection/Wittliff Collections holds several Cormac McCarthy-related collections:
The Cormac McCarthy Papers - The comprehensive archive of Cormac McCarthy's personal papers.
The Woolmer Collection of Cormac McCarthy, which consists of letters between McCarthy and bibliographer J. Howard Woolmer. The Woolmer Collection also includes 140 books and other published materials related to McCarthy. Many are signed and inscribed by the author
The John Sepich Papers include research, correspondence and drafts of works of commentary by John Sepich focusing on the novel, Blood Meridian. Sepich published Notes on Blood Meridian in October, 1993. A revised and expanded edition of Notes on Blood Meridian was published by the University of Texas Press as part of the Southwestern Writers Collection/The Wittliff Collections Book Series in 2008.
The Peter Greenleaf Papers include eight handwritten letters from Cormac McCarthy sent to Peter Greenleaf between 1981-1988.
The Perspectives on Cormac McCarthy Collection is comprised of drafts and proofs of essays by various authors on the works of Cormac McCarthy. The essays were edited by Edwin "Chip" Arnold and Dianne Luce and appeared in Perspectives on Cormac McCarthy, published in 1993.
McCarthy's Drafts of two screenplays: "Whales and Men," and "Cities of the Plain," along with a typescript for McCarthy's stage play "The Stonemason." Donated by Cormac McCarthy and Bill and Sally Wittliff.
Dale L. Walker Collection of Cormac McCarthy-related clippings, reviews, and photocopies.
Also of note: The University of Virginia Special Collections holds the papers of Albert Erskine, McCarthy’s editor for twenty years. http://ead.lib.virginia.edu/vivaead/published/uva-sc/viu03211.xml.frame