Born: 1820-07-10 Lancaster, Pennsylvania
Died: 1872-01-03 Paris, France
Son of George B. Porter, a governor of the Michigan Territory, Andrew Porter was the grandson of Revolutionary War general Andrew Porter, cousin of Civil War general Horace Porter, and cousin once removed of Mary Lincoln. From July 1836 to January 1837, he attended the United States Military Academy. At the beginning of the Mexican War, he volunteered for war service. In May 1846, he received a commission into the U.S. Army as a first lieutenant in the newly created Mounted Riflemen. In May 1847, he received promotion to captain of a company in the Mounted Riflemen, under the command of Persifor F. Smith. Porter and his company participated in General Winfield Scott's expedition from Veracruz to Mexico City. He distinguished himself in several engagements, most notably at Contreras, Churubusco, and Chapultepec. He was breveted major for his gallant and meritorious conduct at Contreras and Churubusco and breveted lieutenant colonel for Chapultepec. After the war, he remained with the Mounted Riflemen, and for the next fourteen years he performed garrison duty in Texas and other parts of the American Southwest. At the beginning of the Civil War, Porter was stationed at Fort Craig, New Mexico Territory. On May 14, 1861, he became colonel of the new 16th U.S. Infantry, and three days later, he received promotion to brigadier general. Transferred to Virginia, Porter commanded a brigade at the First Battle of Bull Run in August. After a short stint as provost marshal of Washington, D.C., he became provost marshal general of the Army of the Potomac, a position he held from August 1861 until the end of the Peninsula Campaign. In August 1862, the War Department sent him to Harrisburg, Pennsylvania to recruit and organize new units. From November 1862 to April 1864, he served as provost marshal of Pennsylvania, but on April 4, 1864, he was mustered out of the service for health reasons, and he resigned his commission on April 20. He spent the remainder of his life traveling abroad for his health.
Gravestone, Section F, Lot 47, Elmwood Cemetery, Detroit, MI; Wm. Hugh Robarts, Mexican War Veterans: A Complete Roster of the Regular and Volunteer Troops in the War Between the United States and Mexico, From 1846 to 1848 (Washington, DC: Brentano's, 1887), 13; Francis B. Heitman, Historical Register and Dictionary of the United States Army(Washington, DC: Government Printing Office, 1903), 1:798; Ezra J. Warner, Generals in Blue: Lives of Union Commanders (Baton Rouge: Louisiana State University Press, 1964), 377-78; John H. Eicher and David J. Eicher, Civil War High Commands (Stanford, CA: Stanford University Press, 2001), 434.