1st Battalion 12th Marines 1st Battalion 12th Marines ( 1 / 12 ) is an artillery battalion comprising four firing batteries and a Headquarters Battery . The battalion is stationed at Marine Corps Base Hawaii and falls under the 12th Marine Regiment and the 3rd Marine Division . The battalion has recently transitioned to its new primary weapon system the M777 lightweight howitzer with a maximum effective range of 30 km . Mission . Provide direct support of the 3rd Marine Regiment in time of conflict . That support may come in the traditional fashion of artillery support to maneuver forces , or by providing batteries to serve as provisional rifle companies . They also have the secondary mission of being the primary providers of civil - military operations ( CMO ) . CMO is defined as the activities of the commander that establish , maintain , influence , or exploit relations between military organizations , Government and civilian organizations and the civilian populace . History . World War II . 1st Battalion 12th Marines came into existence during World War II . The battalion was activated 1 September 1942 , at San Diego , California as the 4th Battalion 12th Marines and assigned to the 3rd Marine Division . During October 1942 , the Battalion relocated to Camp Dunlap , California . They were deployed to Auckland , New Zealand during March 1943 , then redeployed during July 1943 to Guadalcanal . During this period , the Battalion was heavily involved in numerous campaigns including the Battle of Bougainville , Battle of Guam and the Battle of Iwo Jima . After being re - designated on 5 April 1945 as 1st Battalion 12th Marines , the Battalion was relocated during December 1945 to Camp Pendleton , California and as deactivated on 8 January 1946 . 1950s through the 1980s . Five years later , the Battalion was reactivated on 20 June 1951 at Camp Pendleton , California and was assigned to the 3rd Marine Division . In August 1953 , 1st Battalion 12th Marines deployed to Camp Mcnair , Japan and redeployed to South Camp Fuji , Japan during March 1956 . During March and April 1965 , the battalion was called upon to deploy to the Republic of Vietnam . They participated in the Vietnam War from April 1965 to September 1969 , operating from Phu Bai , Danang , Cam Lo , Khe Sanh and Camp Carroll . The battalion after the Vietnam war was reduced to cadre status . During October 1969 , the battalion was re - established at Camp Pendleton , California and assigned to the 5th Marine Division . One year later , in November 1969 , they were reassigned to the 5th Marine Expeditionary Brigade . In April 1971 , the 1 / 12 was reassigned to the 1st Marine Division . The battalion deployed in June 1971 to Kaneohe Bay , Hawaii and was later reassigned to the 1st Marine Brigade . During the 1970s and 1980s , the unit participated in numerous training exercises to remain combat ready . 1st Marine Brigade re - designated on 30 August 1985 as the 1st Marine Amphibious Brigade . In the years that followed , 1st Marine Amphibious Brigade was re - designated as the 1st Marine Expeditionary Brigade . 1990s & the Global War on Terrorism . 1st Battalion 12th Marines participated in Operation Desert Shield and Operation Desert Storm in Southwest Asia during September 1990 to April 1991 . In September 1994 , the Battalion was reassigned to 3rd Marine Division as part of the III Marine Expeditionary Force , Hawaii . From July 2004 through April 2005 , Charlie Battery , 1st Battalion 12th Marines , deployed in support of Operation Iraqi Freedom . They were attached to 1st Battalion 3rd Marines and deployed to Fallujah , Iraq participating in Operation Phantom Fury . They were the lead artillery battery inititating the attack on Fallujah where they fired over 1500 rounds in support of 1st Battalion 8th Marines . From March 2007 through October 2007 and September 2008 through April 2009 , 1st Battalion 12th Marines conducted the provisional mission of Task Force MP operating in the Al Anbar province of Iraq . The battalion is currently the only " stand alone " artillery unit in 12th Marines ; 2nd Battalion was deactivated following due to defense cut - backs and the relocation of 12th Marine Regiment from Camp Foster to Camp Hansen , both in Okinawa . 3rd Battalion maintains its headquarters at Camp Hansen and sources the Unit Deployment Program as the headquarters element for deployed artillery batteries drawn from across the Corps . 3 / 12 ' s permanent firing batteries have been reassigned to other units : Battery K to 2nd Battalion 11th Marines , Battery L to 3rd Battalion 11th Marines , and Battery I to 1st Battalion 11th Marines .