1st Battalion, 5th Marines (1/5) 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. Nicknamed Geronimo, it falls under the command of the 5th Marine Regiment and the 1st Marine Division. The battalion was formed in Mexico in 1914 and has served in every major conflict that the United States has been involved in since then.