The papers of Samuel Peter Heintzelman (1805-1880), consisting of correspondence, diaries, journals, military papers, and miscellany, span the period 1822-1913. The bulk of the material is concentrated in the years 1850-1865. The collection reflects Heintzelman’s career in the regular army and as a major general of volunteers during the Civil War.

The journals run almost without interruption from 1825, the year before Heintzelman graduated from the United States Military Academy, through 1872, three years after he retired from the army. Heintzelman described his surveys of Lake Huron, 1832-1834, his participation in the Creek War and Seminole Wars in Florida, and his activities during the Mexican War. He also discusses the history and culture of Native American groups in the Southwest, especially in Arizona and southern California. Together with the correspondence, the journals reveal in detail Heintzelman’s activities as a corps commander under George Brinton McClellan during the campaigns in Virginia in 1862. Wartime life in northern Virginia and in Washington, D.C., was often noted.

The collection contains little correspondence with members of Heintzelman’s family and with associates in his civilian enterprises, most notably the Sonora Exploring and Mining Company of Arizona. Major correspondents include H. W. Halleck, Joseph Hooker, Philip Kearny, George Brinton McClellan, Edwin McMasters Stanton, and Lorenzo Thomas.