The 1st Marine Regiment is an infantry regiment of the United States Marine Corps based at Marine Corps Base Camp Pendleton, California. The regiment is under the command of the 1st Marine Division and the I Marine Expeditionary Force. The 1st Marine Regiment is also sometimes referred to as "Regimental Combat Team 1" or "Inchon". Subordinate units The regiment comprises four infantry battalions and one headquarters company: Headquarters Company 1st Marines 1st Battalion, 1st Marines (1/1) 2nd Battalion, 1st Marines (2/1) 3rd Battalion, 1st Marines (3/1) 1st Battalion, 4th Marines (1/4) – (1/4 is assigned to the 1st Marine Regiment for the purpose of facilitating 4th Marines as a "host" regimental headquarters for battalions on unit deployment program assignments to 3rd Marine Division on Okinawa.) History The 1st Marines were activated in Philadelphia, Pennsylvania on 27 November 1913. At this time, it bore the designation of 2nd Advanced Base Regiment. During the 1st Marine Regiment's early years, it was primarily employed as a combat force in the so-called Banana Wars, and in the Caribbean area. The first of these engagements occurred in April 1914, when the regiment landed and seized the Mexican port of Vera Cruz. They next participated in the Haitian campaign (1915–1916) and the Dominican Republic campaign (1916). On 1 July 1916, this organization was re-designated as the 1st Regiment of Marines. In December 1918, the 1st Regiment returned to the Caribbean and was deployed to Cuba for approximately six months. Following its second Dominican tour of duty, it was deactivated; but it was subsequently reactivated at Quantico, Virginia on 15 March 1925. The Regiment received its present designation of 1st Marines on 10 July 1930. The 1930s was a period of inactivity in the 1st Marines' history, as the unit was in a deactivated status during most of this time. World War II was the occasion for the next reactivation of the Regiment on 1 February 1941 at Culebra, Puerto Rico as part of the 1st Marine Division. World War II The 1st Marines stood at a low state of readiness at the beginning of the war, having just been reconstituted from cadre status; however, the regiment did possess very strong leadership at the higher levels. In June 1942, the 1st Marines set sail from San Francisco on board a mix of eight ships headed for the South Pacific. The 1st Marines landed on the island of