Benjamin Henry Grierson (July 8, 1826 – August 31, 1911) was a music teacher, then a career officer in the United States Army. He was a cavalry general in the volunteer Union Army during the Civil War and later led troops in the American Old West. He is most noted for an 1863 expedition through Confederate-held territory that severed enemy communication lines between Vicksburg, Mississippi and Confederate commanders in the Eastern Theater.