Douglas Putnam (August 21, 1838 – August 11, 1918) was a U.S. Army colonel in the American Civil War. After serving at the Battle of Shiloh he became a member of General Ulysses S. Grant's staff. Douglas was the son of Douglas and Mary A. (Hildreth) Putnam, both from Ohio. His mother was the daughter of the famous Doctor and historian Samuel Hildreth, from Marietta, Ohio. Colonel Putnam attended Marietta College and graduated in 1859. In 1861 he entered the volunteer army and commanded the Ninety-Second Ohio Volunteer Infantry, during the Chattanooga campaign. He was wounded at the Battle of Missionary Ridge, and subsequently mustered out in 1864 with the rank of Lieutenant-Colonel. Putnam was also a historian and writer and produced several historical works, including an eyewitness account of the Battle of Shiloh.