The collection includes a letter from Capron's sister to her mother, a letter to Capron from his parents and one letter from Henry C. Barrett to Nannie and Cyrus Fairley, Camp Cleveland, Ohio, 29 December 1863. Written from Fort Kearney and Cottonwood Springs, Nebraska Territory. Also includes 12 envelopes and a daguerreotype portrait of Capron.

Includes ms. account of the Sully campaign against the Indians of the West, 1863-1865 (59 leaves.), written in 1920 from memoranda, notes and correspondence; ms. account of the Feenan genealogy (12 leaves), photographs, letters, newspaper clippings, documents, etc.