Carte view of Lieutenant Colonel John P. Sanderson. Sanderson was appointed chief clerk of the War Department in March, 1861. He resigned from that position to become lieutenant colonel of his son’s regiment, the 15th U.S. Infantry on May 14, 1861. He reported to Newport Barracks and assumed command of the regiment’s headquarters shortly after. In July, 1863, he was appointed colonel of the 13th U.S. Infantry and later accepted a position as an aide to General William Rosecrans, where he served during the Battle of Chickamauga. After Rosecrans was relieved of his command Sanderson went with him. When Rosecrans took command of the Department of the Missouri late in January 1864, he brought Sanderson with him serving as Provost Marshal General of the Department of the Missouri. Sanderson was later accused of cowardice during the Battle of Chickamauga by an assistant to Edward Stanton. This initially held up Congressional approval of his appointment, but Rosecrans soundly refuted this and wrote a letter in defense of Sanderson. He would serve in that position until his death after a month’s illness at St. Louis, Missouri on October 14, 1864. Back marked out of Springfield, Ohio.