4th Light Armored Reconnaissance Battalion (4th LARB) is a fast and mobilized armored terrestrial reconnaissance battalion of the United States Marine Corps reserve. Their primary weapon system is the LAV-25 and they are part of the 4th Marine Division and Marine Forces Reserve. The unit headquarters is at Camp Pendleton, California, but other units in the battalion are located throughout the United States. 4th LAR Bn is the largest combat battalion in the Marine Corps, with 7 companies.