Horatio Collins King Collection. MC 1999.9 Dickinson College Archives and Special Collections, Carlisle, PA.
King, Horatio Collins. Souvenir: A Book of Songs and Poems. No publisher or copyright information.
King, Horatio Collins. An Account of the Visit of theThirteenth Regiment, N.G.S.N.Y. to Montreal, Canada, May 1879. Brooklyn, Eagle Job and Book Printing, 1879.
King, Horatio. "Buchanan's Loyalty," The Century, vol. 23, issue 2, p. 289-297. http://cdl.library.cornell.edu/cgi-bin/moa/sgml/moa-idx?notisid=ABP2287-0023-74
Report of the New York State Commission, State of New York Fiftieth
Anniversary of the Battle of Gettyburg, 1913. J.B. Lyon Company:
Davidson, James West, et al. Nation of Nations: A Concise Narrative of the American Republic. New York: Overture Books, 1996
Dearing, Mary R. Veterans in Politics: the Story of the G.A.R. Westport: Greenwood Press, 1972.
Rulkotter, Marie L. Civil War Veterans in Politics. Madison: University of Wisconsin Library, 1938.
Stegman, Col. Lewis R., Sketch of Horatio C. King. New York: Macgowan & Slipper Printers, 1899. 17 pgs.