2:9th Marines

The 2nd Battalion, 9th Marines (2/9), known as "Hell in a Helmet," was activated during World War II in 1942 and served with distinction in the Pacific, notably at Bougainville, Guam, and Iwo Jima. The battalion saw heavy combat during the Vietnam War, participating in major operations such as Operation Dewey Canyon and defending Khe Sanh. After several periods of deactivation and reactivation, 2/9 served in the Gulf War and later participated in deployments supporting the Global War on Terrorism. The battalion was last deactivated in 2015 as part of the Marine Corps' force structure realignment.