Dr. James Madison DeWolf (January 14, 1843 – June 25, 1876) was an acting assistant surgeon in the U.S. 7th Cavalry Regiment who was killed in the Battle of the Little Big Horn. Born in Mehoopany in Wyoming County, Pennsylvania, DeWolf was a farmer prior to the American Civil War. In August 1861, he enlisted in the Union Army in the 1st Pennsylvania Artillery at the age of 17. He first saw combat at the First Battle of Bull Run. He was promoted to Corporal, but was severely wounded in the arm and discharged in October 1862. He re-enlisted in September 1864 in Battery A, 1st Pennsylvania Artillery, serving in that battery until his discharge on June 14, 1865.