Who was the youngest general in the Civil War?

Galusha Pennypacker. At the age of 16 he enlisted as a quartermaster sergeant in the 9th Pennsylvania Infantry Regiment. In October 1861, he was appointed a major in the 97th Pennsylvania, for which he had helped recruit a company of men. Pennypacker’s greatest moment of the war came at the Second Battle of Fort Fisher, January 15, 1865, where he received what many thought a fatal wound. General Terry promised he would receive a brevet promotion for his conduct that day, and called him “the real hero of Fort Fisher.” Pennypacker much later was awarded the Medal of Honor, with a citation reading: “He gallantly led the charge over a traverse and planted the colors of one of his regiments thereon; was severely wounded.”  He survived his wounds after 10 months in the hospital and on February 18, 1865, received a full promotion to brigadier general of volunteers at age 20, making him the youngest officer to hold the rank of general to this day in the United States Army. Pennypacker stayed in the Army after the Civil War, serving on the frontier as Colonel of the 34th U.S. Infantry, transferring in 1869 to the 16th U.S. Infantry, which he commanded until his retirement in July 1883.