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 manuscript accounts of the early settlement of Boise, Idaho, troubles with the Indians, etc., as well as documents, newspaper clippings, etc.