Mark Rambo Supplee was born in Upper Merion on April 11, 1836 to Alexander and Jane Supplee. He was one of three children. Mark’s father was a farmer and by 1860 Mark was beginning to follow in his footsteps. However, when the Civil War began in 1861, he enlisted with the 51st PA Volunteer Regiment on September 23, 1861. He initially enlisted as an Orderly Sergeant but by June 1862 had been promoted to Second Lieutenant of Company I.
Mark fought with the unit until his three year enlistment ended on November 15, 1864. During that time he fought with the Regiment in major battles such as Antietam, Fredericksburg and Vicksburg. His unit also fought in the battles of the 1864-65 Overland Campaign between U.S. Grant and Robert E. Lee.
Mark settled back in Upper Merion following the war. On February 17, 1869 he married Hannah Baker at the Lower Providence Presbyterian Church in Eagleville. Together they had four children. He and his wife continued to live in Upper Merion where he once again picked up farming. Mark died on July 18, 1901. His wife survived him by nearly 26 years and they are now buried together in the Montgomery Cemetery in Plot A-229.