9th Marine Regiment ( United States ) The 9th Marine Regiment was an infantry regiment of the United States Marine Corps . Formed during World War II , it served until the early 1990s when it was deactivated to make room for three light armor reconnaissance battalions . Battalions of the Ninth Marine Regiment began to be reactivated in 2007 as part of the Marine Corps ' plan to increase its end strength by 27 , 000 over the following five years . Current Units . The regiment is composed of three infantry battalion s and one headquarters company : History . Early years . The 9th Marines were activated at Quantico , Virginia on November 20 , 1917 . A month later , they deployed to Guantanamo Bay , Cuba and were attached to the 3rd Marine Brigade . That same month , they redeployed with the brigade to Galveston , Texas in case of any German operation in the Caribbean or in Mexico . After World War I , the regiment was deactivated in Philadelphia , Pennsylvania on April 25 , 1919 . On December 1 , 1925 , the regiment was reactivated as a reserve organization whose mission was to train and maintain at a high degree of preparedness a group of “ civilian ” Marines . World War II . The 3rd Battalion 9th Marines was reactivated at Camp Elliot , San Diego on February 12 , 1942 . In the following months , the rest of the battalions were also reactivated on January 1 , 1942 when the regiment officially re - formed . They were attached to the 3rd Marine Division at Camp Pendleton on September 16 , 1943 . The 9th Marines fought as part of the 3rd Marine Division on the islands of Bougainville , Guam , and Iwo Jima during WW2 . The Regiment was deactivated at Camp Pendleton on December 31 , 1945 . Vietnam War . On March 8 , 1965 , 9th Marines came ashore at My Khe Beach ( better known as China Beach ) as the first conventional ground combat unit in South Vietnam . Their mission was to defend the air base at Da Nang . The first significant contact was in April 1965 . The regimental headquarters arrived in country in July of that year . The Regiment saw action in Vietnam ’ s I Corps , primarily in Quang Tri and Thua Thien provinces , although a number of its earlier operations were also conducted in the southern I Corps provinces of Quang Nam , Quang Tin , and Quang Ngai . The 9th Marines served as a vital stop to the North Vietnamese penetrations across the DMZ and from along the Ho Chi Minh Trail in Cambodia . Some of its early operations included Double Eagle , Macon and Prairie . In April and May 1967 , elements of the regiment defeated two NVA Regiments in the Hills north of Khe Sanh . In Operation Buffalo , elements of the 1st Battalion , 9th Marines made contact north of Con Thien with regimental - size NVA forces in an engagement that lasted through May , accounting for over 1300 enemy dead . In one of the most successful operations of the war , the regiment conducted Operation Dewey Canyon in the A Shau Valley , cut by the Song Da Krong river . The 9th Regiment exacted a deadly toll on the NVA . These actions precluded another build - up and assault from Route 622 from Laos into South Vietnam as the NVA had the year before during the Tet Offensive . Operation Dewey Canyon netted , among other weaponry , 16 artillery pieces , 73 anti - aircraft guns , hundreds of thousands of rounds of ammunition , 92 trucks , and hundreds of thousands pounds of rice . In the words of Gen Stillwell in his report to Gen Abrams on Operation Dewey Canyon : “ . . . this ranks with the most significant undertakings of the Vietnam conflict in the concept and results . . . ” The 9th Marines were part of the first redeployments from Vietnam in the summer of 1969 . In July 1969 the regiment deployed to Camp Schwab , Okinawa and was reassigned in August 1969 to the 9th Marine Amphibious Brigade . The 9th MAB was then reassigned during November 1969 to the 3rd Marine Division ( 3 MarDiv ) . Deactivation ( 1994 ) . The 9th Marines were deactivated in the budget cuts of 1994 . A nucleus of staff and support personnel were maintained to reconstitute the regiment when needed . This was done in the belief that the necessary riflemen would be easily recruited in time of emergency or war . On September 2 , 1994 the 2nd Battalion was deactivated and redesignated the 2nd Battalion , 4th Marines and the 3rd Battalion was deactivated and re - designated the 3d Battalion , 4th Marines . On September 9 , 1994 the 1st Battalion was deactivated and redesignated as the 2nd Battalion , 1st Marines . Reactivation ( 2007 ) . As part of the effort to expand the Marine Corps to 202 , 000 Marines by the end of 2011 , the battalions of the 9th Marines began reactivation in 2007 . The 1st Battalion , 9th Marines ( 1 / 9 ) reactivated on April 18 , 2007 , the 2nd Battalion reactivated in July 2007 , and the 3rd Battalion reactivated in May 2008 . Each battalion falls under existing regimental headquarters — 1 / 9 with the 8th Marine Regiment , 2 / 9 with the 6th Marine Regiment and 3 / 9 with the 2nd Marine Regiment . Medal of Honor recipients . 8 Marines from the 9th Marine Regiment have received the Medal of Honor : 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 . During its existence 9th Marines were presented with the following awards :