The Harvey Harris Cluff collection (1893-1944) consists of a scrapbook of clippings on Cluff's life and career. Also included are a biographical sketch of his wife, Frances Amelia Worsley Cluff, 1841-1934, genealogical notes, poems, letters, and essays on various subjects. Harvey Harris Cluff was a Utah attorney who served as attorney general of Utah from 1920 to 1928.

The Edward W. Clyde papers (1940-1991) contain correspondence, case files, essays and speeches, and scrapbooks. Edward W. Clyde (1917-1991) was a Salt Lake area lawyer involved in many water reclamation cases.

The Edward F. Coburn correspondence (1885-1901) contain a set of seventeen letters to various people; Dorothy to her father, correspondence to Edward F. Coburn (Ed), and subscription correspondence from The History Company.

The Paul Coburn letter (1864) is directed to Nat Stein, ALS, of Viginia City, Idaho. The letter is printed on Overland Stage Company letterhead, concerning the disposition of a grey horse by warrant of "Mrs. Slade." Along with the letter is a descriptive article, written by Richard Saunders in 2010, about the provenance of the letter and historical background information.

The Cochranism collection (circa 1816-1983) consists of photocopied primary and secondary sources on the life of Jacob Cochran and the sect which he founded, including photocopies of legal documents. Also included is correspondence to various libraries and institutions seeking information on Jacob Cochran and Cochranism, particularly on whether any members of the Cochran sect later joined the LDS Church.

The Cornelius Cole letter (1866) was written by Cole to William Pitt Fessenden. Cornelius Cole (1824-1924) was a United States Representative and later a United States Senator representing California. As a Republican Senator, he represented the people of California from 1867-1873.

The Katharine Hogle Cole papers (1938-1999) document a life dedicated to politics. Included in the collection is her extensive correspondence with Eileen Bernal, a founder of the Peace Councils Movement in England, and wife of Marxist activist, John Bernal. More personal than political, the correspondence documents a friendship of 30 years, until Eileen Bernal's death in 1990.

The Jonathan Coleman papers (1990-1992) contains research, notes, histories, family documents, correspondence and finished and draft manuscripts for the book, At Mother's Request: A True Story of Money, Murder, and Betrayal, that was written about the Salt Lake City Bradshaw murder.

The Ronald Coleman papers (1866-1983) contain photocopies of news clippings, letters, photographs and personal documents related to African American families of Grand Junction, Colorado.

The Alice Colton papers (1933-1940) consist of a letter and a certificate of membership to Theta Alpha Phi.

The Byron O. Colton family papers (1905-1947) consist of correspondence to Byron Owen Colton in Maeser, Utah, from William H. Smart of Roosevelt; correspondence from family and friends; business records and certificates; and a typescript history of the Roosevelt, Utah, LDS Stake, among other papers. Byron Owen Colton (b. 1882) was an LDS Church bishop in the Uintah Stake and later succeeded William H. Smart as president of that stake.

The Committee to Stop East-West Light Rail records (1999-2000) contain a booklet published by those against the light rail spur to the University of Utah. There are also some mailing certificates and a letter of reasons the spur should not be built.

The John A. Compton family papers (circa 1882-1941) consist of records of the Compton family, primarily concerning Allen Compton, son of John A. Compton. Included is a genealogy and correspondence among family members concerning the history of the family.

The Andrew Wood Cooley family papers (1837-2021) consist of biographical and genealogical materials relating to Andrew Wood Cooley (1837-1887) and his family. Andrew Cooley was a prominent member of the LDS Church during the nineteenth century.

The Everett L. Cooley papers (1775-2006) consist of autobiographical information, articles, book reviews, papers, correspondence, manuscripts, documents, oral history materials, speeches, meeting minutes, recommendations, memos, newsletters, bulletins, programs, and newspaper clippings. Cooley is professor emeritus of history at the University of Utah and the retired director of special collections in the University of Utah Marriott Library.

The J. Raymond Cope letters (1945) are carbon copies. One is from J. Raymond Cope, a Unitarian minister, and the other from LDS Church president, George Albert Smith. The letters discuss a leaflet supposedly distributed by the LDS Church, entitled "Sustaining the General Authorities of the Church."

The Nancee Cortés papers (1942-2011) contain documents related to the life and career of Nancee Cortés (b. 1935), professional ballet dancer and former faculty member at the University of Utah. The materials in the collection are listed alphabetically by subject and include ballet and music programs, correspondence, news clippings, reports, calendars, brochures, and scrapbooks all outlining Cortés' life-long dedication to the performing arts.

The Ramiro Cortés papers (1933-1988) document the personal and professional life of the first significant Mexican-American composer, Ramiro Cortés (1933-1984), of serious twentieth-century music in the United States.