1st Battalion, 4th Marines (1/4) is an infantry battalion in the United States Marine Corps based out of Marine Corps Base Camp Pendleton, California consisting of approximately 800 Marines and sailors. They fall under the command of the 1st Marine Regiment and the 1st Marine Division.

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".