Included is Cox's correspondence, circa 1880 until his death in 1919, with architects, painters, sculptors, and writers including Bernard Berenson, Edwin Howland Blashfield, Will Hicock Low, John La Farge, Henry Oliver Walker, H. Siddons Mowbray, Theodore Robinson, Elliott Daingerfield, Lucia Fairchild Fuller, Howard Pyle, William A. Coffin, Russell Cowles, Daniel Chester French, Irving R. Wiles, James Monroe Hewlett, Harry Wilson Watrous, Edward R. Simmons, Maxfield and Stephen Parrish, Augustus Saint-Gaudens, Louis Saint-Gaudens, John C. Van Dyke, Wendell P. Garrison, Richard Watson Gilder, Robert Underwood Johnson, the architectural firm of McKim, Mead & White, Stanford White, Charles F. McKim, Cass Gilbert, Charles Adams Platt, and others. Of note are 136 from Cox to lawyer and author Leonard E. Opdyke. Correspondence, circa 1870-1922, with family members, particularly his father, Jacob Dolson Cox (a Union officer), his mother, Louise Howland King Cox (a painter), and his brother Jacob Dolson Cox, Jr. (a Cleveland industrialist and founder of the Cleveland Twist Drill Company). Correspondence of various other family members either among themselves, beginning circa 1860, or with Kenyon Cox is included. Also, manuscripts of Cox's essays, addresses, articles, and other writings on art, circa1870-1919; poetry; and juvenilia.
