2nd Battalion 10th Marines

The 3rd Battalion, 9th Marines (3/9) is an infantry battalion of the United States Marine Corps. Formed during World War I it served until the early 1990s when it was re-designated as 3rd Battalion, 4th Marines (3/4) during a realignment and renumbering of the Marine Corps' infantry battalions, following the deactivation of the 9th Marine Regiment.