This collection of letters and notes relates to Geronimo and other Chiricahua Apache prisoners of war. The letters were written at Mount Vernon Barracks and Fort Sill and include documents signed by Geronimo. There is some documentation of the Apache culture. Provenance note from Agnes K. Capron, wife of Allyn Capron, dated March 26, 1938, to George Gustav Heye. Notes by Capron, 7 pages and copies of notes about Apache culture, legends, religion, thoughts about white men. 5 leaves of notes by Capron taken at Camp Apache, Fort Sill, Oklahoma, 1890, discussing the Apache medicine mask and legend of the medicine hat and chief. Note discussing interview with Geronimo about his childhood, and fights with Mexicans. Letter from Mount Vernon Barracks, dated July 3, 1894, from Capron giving statistics and information, living conditions, about Apaches living in the camp for the month of June. Additional note, same as previous, for October 1895. Letter from Lt. William Wallace Wotherspoon from Mount Vernon, presumably to Capron, dated September 30, 1891, same as previous, statistics for September 1891.

Letter from Capron at Apache Camp, Fort Sill, Oklahoma, September 1, 1895 to Captain Hugh L. Scott, same as previous for the month of August 1895, mentions Geronimo specifically. Note from Capron, presumably from Mount Vernon, describing the surrender and transfer to Mount Vernon of the Chiricahua and Warm Springs Apache and Geronimo. This letter makes note of white women who were living with the tribe. Additional note from an undecipherable person to Capron, similar to previous. Also included in collection are two receipts from 1896, one to Scott, one to Capron, for payments for police services rendered; these are signed by Geronimo.