3rd Battalion 1st Marines 3rd Battalion 1st Marines ( 3 / 1 ) is an infantry battalion in the United States Marine Corps based out of Camp Horno on Marine Corps Base Camp Pendleton , California . Nicknamed the " Thundering Third " , the battalion consists of approximately 1220 Marines and Sailors and falls under the command of the 1st Marine Regiment and the 1st Marine Division . History . Beginnings . 3rd Battalion , 1st Marines was activated on 1 March 1941 at Guantanamo Bay , Cuba and assigned to the 1st Marine Division . In April of that year , they were relocated to Marine Corps Recruit Depot Parris Island , South Carolina ; the unit was subsequently deactivated in October of that year . World War II . On 16 February 1942 , 3 / 1 was re - activated at New River , North Carolina . In July 1942 , they deployed to Wellington , New Zealand and participated in the following World War II campaigns : Guadalcanal , Eastern New Guinea , New Britain , Peleliu and Okinawa . Beginning in April 1946 , they participated in the occupation of North China . The battalion was again deactivated on 20 March 1947 as part of the post - war drawdown of forces . Korean War . The start of the Korean War saw the reactivation of 3 / 1 on 4 August 1950 at Marine Corps Base Camp Pendleton , California and their quick deployment to Korea in September . The battalion ' s first action was at the Battle of Inchon in September 1950 . Following the recapture of Seoul , 3 / 1 , along with the rest of the 1st Marine Division , was put back on ship and sailed around to the east coast of Korea . They eventually landed at Wonsan ino late October and from there participated in the Battle of Chosin Reservoir . During the battle they were the only battalion from the Chesty Puller ' s 1st Marine Regiment to make it as far north as Hagaru - ri . After the withdrawal from Chosin , the battalion took part in fighting on the East Central Front and Western Front for the remainder of the war . After the Korean Armistice Agreement was signed , they participated in the defense of the Korean Demilitarized Zone from July 1953 to April 1955 . In April 1955 , the battalion re - located to MCB Camp Pendleton , California . From October to December 1962 , 3 / 1 was part of the amphibious task force sent to the Caribbean in response to the Cuban Missile Crisis . Vietnam War . From January 1966 to May 1971 , the battalion fought in the Vietnam War , operating from Chu Lai , Da Nang , Thang Binh , Thanh Thuy , Cua Viet , Ca Lu Combat Base , LZ Stud ( Vandergrift ) , Route 9 , An Hoa , and Hoa Vang . In May 1971 , they re - located to MCB Camp Pendleton , California . Persian Gulf War & the 1990s . The battalion deployed to Saudi Arabia in December 1990 in support of Operation Desert Shield and in March 1991 , they transitioned to combat operations during Operation Desert Storm . May 1992 brought a short drive up Interstate 5 to Los Angeles to aid local police in Riot Control Operations during the 1992 Los Angeles Riots February and March 1995 saw a deployment to Somalia to support Operation United Shield , helping the remaining UN troops evacuate . The next major deployment was in October 2000 to support Operation Determined Response . Global War on Terror . Operation Iraqi Freedom . 3rd Battalion , 1st Marines deployed to Kuwait in January 2003 and in March of the year took part in the 2003 invasion of Iraq , including the Battle of Nasiriyah . The battalion re - deployed to Camp Pendleton in the summer of 2003 . The unit then re - deployed to Iraq in mid - 2004 and was based near Fallujah . They were the main effort in November 2004 during in Operation Al Fajr ( pronounced Al Fad - jer ) , the retaking of the city of Fallujah . Before the assault commenced , the operation was known as Operation Phantom Fury . 3rd Battalion , 1st Marines was part of the composition of RCT 1 . RCT 1 was partly responsible for clearing the infamous Jolan District among others . Alongside RCT 7 , four Marine battalions ( including 1 / 3 , 1 / 8 , and 3 / 5 ) and various US Army units reclaimed the city of Fallujah from unrest . The battalion re - deployed back to Iraq in September 2005 and were attached to 2nd Marine Regiment ( known as Regimental Combat Team 2 ) , and on 20 February 2006 were attached to the 7th Marine Regiment ( known as Regimental Combat Team 7 ) in western Iraq , carrying out security and stabilization operations . The Battalion returned to Camp Pendleton at the end of March . On 10 April 2007 , 3 / 1 deployed as the ground combat element of the 13th Marine Expeditionary Unit . They were ordered into Iraq as part of Operation Phantom Thunder . Operating north of Fallujah and Karmah in the Thar Thar region in AO Anaheim , MARSOB units attached to the MEU were operating for several days before the ground combat element began operating on 15 June 2007 . They were to establish a coalition presence in an area that had only had 14 days of coalition presence since the invasion in March 2003 . 3 / 1 finished operations in Iraq after 90 days of operating on 20 September 2007 and soon after re - embarked on the naval strike group and set sail for the United States and returned to Camp Pendleton on 17 November 2007 . 3 / 1 deployed to Okinawa in July 2008 as part of the ground combat element of the 31st Marine Expeditionary Unit . Haditha killings . As of December 2006 , Marines from Kilo Company ( K / 3 / 1 ) were under investigation for their actions on 19 November 2005 after " Time magazine " published an article accusing them of killing 24 unarmed Iraqi civilians , including 11 women and children . Residents of Haditha in western Iraq claim that the Marines killed 15 civilians in response to the death of Lance Cpl . Terrazas by an improvised explosive device . The incident is currently under investigation . According to a 29 May 2006 report by " The Times " , Lieutenant Colonel Jeffrey R . Chessani was the commanding officer and was removed along with Captain Luke McConnell . Due to lack of evidence , the case against LtCol Chessani was dismissed " without prejudice , " on 17 June 2008 . An appeal was filed 19 June 2008 by the assigned prosecutors in the case . Operation Enduring Freedom . In April 2010 , 3 / 1 deployed to Helmand Province , Afghanistan in support of Operation Enduring Freedom . The battalion conducted combat operations in the area , including activity in Koshtay and Safar in Garmsir District , and returned to Camp Pendleton in November 2010 . Medal of Honor recipients from 3 / 1 . Marines from the 3 / 1 have been awarded the Medal of Honor for actions during World War II and the Korean War . Unit awards . A unit citation or commendation is an award bestowed upon an organization for the action cited . Members of the unit who participated in said actions are allowed to wear on their uniforms the awarded unit citation . 3 / 1 has been presented with the following awards :