Sylvester Mowry (1830-1871) was an American soldier, explorer, miner, politician and author. In 1852, he was graduated from the United States Military Academy. In 1858 he resigned from the Army at Fort Yuma, and was twice elected as delegate to Washington for the proposed territory of Arizona, but Congress, not recognizing Arizona as an organized territory, refused to seat him. In 1860 he was appointed by President Buchanan a commissioner to establish the boundary-line between California and Nevada, but he was removed in 1861 on political grounds. He was arrested and imprisoned at Fort Yuma on a charge of disloyalty, but established his innocence. He went to England subsequently for his health, and died there. He wrote on subjects connected with the far west in magazines and other periodicals. His works included: Memoir of the Proposed Territory of Arizona (1857), Geography and Resources of Arizona and Sonora (1863) and Arizona and Sonora: The Silver Region of North America (1864).