The first finisher of the 34th Marine Corps Marathon was Lt. Cmdr. John Mentzer, 33, of Portsmouth Naval Shipyard, Maine with a time of 2:21:47. Nearly 21,000 runners crossed the start line at today’s Marine Corps Marathon. The 26.2 mile race took participants on a journey through the streets of Arlington, Va., and Washington, D.C. culminating with a finish at the Marine Corps War Memorial. - The first finisher of the 34th Marine Corps Marathon was Lt. Cmdr. John Mentzer, 33, of Portsmouth Naval Shipyard, Maine with a time of 2:21:47. Nearly 21,000 runners crossed the start line at today’s Marine Corps Marathon. The 26.2 mile race took participants on a journey through the streets of Arlington, Va., and Washington, D.C. culminating with a finish at the Marine Corps War Memorial.