This collection consists primarily of letters written to Loomis from Yates. Other correspondents with Loomis include DeWitt C. Hartwell, Louis D. Hubbard, John Pope and Leonard Swett. Other correspondents with Yates include Jessie K. Dubois, Charles Anderson, C.O. Wilcox, John M. Snyder, Folsom Dorsett and William Pickering. Other documents include an Illinois attorney license certificate for Loomis, his appointment as first assistant adjutant general and Loomis family genealogy papers.
John S. Loomis was born on April 22, 1835 in Lafayette, Indiana. He was married to Emily True in New York on March 29, 1860. He and his wife moved to Quincy, Illinois before the start of the Civil War. Loomis was appointed the first assistant adjutant general of the state of Illinois in July 1861 by Governor Richard Yates. After the war he was appointed an Assistant Special Treasury Agent for a district in Virginia. Loomis later worked as a railroad land agent. He died in 1887.