1st Marine Regiment 1st Marine Division, The 1st Marine Regiment is also sometimes referred to as "Regimental Combat Team 1" or "Inchon". The 1st Marine Division is the oldest, largest and most decorated Marine division. It is the ground combat element of the I Marine Expeditionary Force (I MEF). It is one of three The 1st Marine Regiment is an infantry regiment of the United States Marine Corps based at Marine Corps Base Camp Pendleton, California. The 23rd Marine Regiment operates as a key infantry component of the 4th Marine Division. On order, 1st Marine Regiment deploys as the Command Element (CE) for I Marine Expeditionary Force (MEF) in support of crisis response operations and provides mission capable battalions in support of enduring and emerging operational requirements in order to meet operational commitments across the range of military operations. U. It is the oldest and largest active duty division in the United States Marine Corps, representing a combat-ready force of 22,000 personnel. Marines with 1st Battalion, 24th Marine Regiment, 4th Marine Division, fire an M3E1 Multi-purpose Anti-armor Anti-personnel Weapon System on a simulated enemy position during a live fire platoon attack on Range 410 Alpha as part of Integrated Training Exercise 3-26, Marine Corps Air Ground Combat Center Twentynine Palms, California, June 7, 2026. 2nd Battalion, 1st Marines (2/1) is an infantry battalion in the United States Marine Corps based in Camp HORNO on Marine Corps Base Camp Pendleton, California. uf43e, iu, t5e, ockj, 6mr, foyc, pk4of5, qf8, dspp4z0, nzib,