Collection
- Calvin Thomas Papers, 1838-1940 (majority within 1872-1919)1
- Carl A. Russell papers, 1950, undated1
- Carl Ernest Schmidt papers, 1892-19351
- Carlisle Family papers, 1860-19721
- Carr family papers, 1861-19301
- Charles A. Simpson papers, 1910-19321
- Charles Adam Weissert papers, 1893-19471
- Charles Brady Ryan papers, 1916-19191
- Charles David Williams papers, 1878-19231
- Charles Douglas Roe papers, 1917-1931 (majority within 1917-1919)1
- Charles E. Lewis papers, 1917-1958 (scattered dates)1
- Charles S. Smith papers, circa 1875-19231
- Chauncey C. Wade papers, 1917-19321
- Clara Hadley Wait papers, 1893-2001 (majority within 1893-1919)1
- Clarence C. Miller letters, 19191
- Clarence G. Scheu diary, 1918-19191
- Clarence J. Primm papers, 1918-19511
- Claude Halstead Van Tyne papers, 1885-19301
- Cleo M. Colburn papers, 1918-19191
- Clippert Family papers, 1863-19621