3rd Battalion 5th Marines 3rd Battalion 5th Marines ( 3 / 5 ) is an infantry battalion in the United States Marine Corps . The battalion , nicknamed " Dark Horse " , is based out of Marine Corps Base Camp Pendleton , California and consists of approximately 1 , 000 Marines and Sailors . They fall under the command of the 5th Marine Regiment and the 1st Marine Division . History . World War I . 3rd Battalion , 5th Marines , along with the 5th Marine Regiment , was first organized on June 8 , 1917 as the United States prepared for World War I . The battalion was composed of four companies : the " 16th " , " 20th " , " 45th " and " 47th " . Six days later , manned by Spanish - American War and Boxer Rebellion veterans along with a large number of raw recruits , they set sail for France . They participated in campaigns and battles such as Bois de Belleau , Vierzy , Château - Thierry , Pont - a - Mousson , Limey Sector , Fleury , Muese Argonne , Blanc Mont , St Michiel , Leffincourt and Soissons . The French Government recognized the young battalion by presenting it the Croix de guerre along with the Fourragère and changing the name of a French landmark , Belleau Wood , to " " Bois de la Brigade de Marine " " or " Wood of the Marine Brigade " . Interwar period . In August 1919 , the Battalion was deactivated following World War I and less than two years later , in May 1921 , the 3rd Battalion , 5th Marines was reactivated . For the next several years , men of the 3rd Battalion served in the Caribbean and at home , guarding the U . S . Mail . In March 1927 , the 3rd Battalion deployed to Nicaragua to help stabilize the government against overthrow attempts by rebel forces . For the next six years , the Battalion aided the Nicaraguan government until peace was finally restored . The job done , the 3rd Battalion was once again disbanded on January 1933 . In November 1934 , the 3rd Battalion was reactivated for the fourth time , only to be deactivated in March 1935 . World War II . Shortly before World War II in April 1940 , 3rd Battalion was again reactivated . The fighting in World War II found the Marines of 3 / 5 at Guadalcanal , New Britain , Peleliu , and Okinawa . At Peleliu , they were the last Marine battalion to be shipped out before the army took over . In April 1946 , their mission accomplished , 3rd Battalion was disbanded and most of the Pacific veterans returned to civilian life . Korean War . During October 1949 , 3rd Battalion , 5th Marines was reactivated on Guam . During August 1950 , the Battalion deployed to fight the Communist force invading the Republic of Korea . The battalion fought at such places as the Pusan Perimeter , Inchon , Seoul and Chosin Reservoir . At the close of hostilities , the 3rd Battalion returned to the United States , settling at MCB Camp Pendleton . The battalion ' s nickname " Darkhorse " sprang from the radio call sign of its commander in Korea , Col . Robert Taplett , who was known as Darkhorse Six . Vietnam War . From June 1966 to March 1971 , the 3rd Battalion fought in Vietnam . They fought as such places as Chu - Lai , Da Nang , Quang Nam , Operation Union and Union II in the Que Son valley — received a Presidential Unit Citation , the Battle of Hue , An Hoa , Operation Swift in the Que Son Valley — received a second Presidential Unit Citation , and the Ross Combat Base . 3 / 5 was not associated with the name Darkhorse during the Vietnam War . Our Battalion patch was Consummate Professionals Gulf War and the 1990s . On December 1 , 1990 , the battalion deployed to the Middle East in support of Operation Desert Shield as a Battalion Landing Team ( BLT ) , with the 5th Marine Expeditionary Brigade ( MEB ) . As part of the largest amphibious task force assembled since Vietnam , the battalion was augmented with mobilized Marine Corps Reserve units from 4th Assault Amphibian Battalion , Tow Platoon , 23rd Marines , 4th Marine Division , and 4th Tank Battalion . 3 / 5 distinguished itself in combat operations in Al Wafrah , Kuwait during Operation Desert Storm as Mechanized Combined Arms Task Force ( MCATF ) . En route home from hostilities , 3 / 5 participated in Operation Sea Angel , delivering critical food , supplies , and humanitarian assistance to the cyclone ravaged country of Bangladesh . Iraq War . 3rd Battalion was deployed for the 2003 invasion of Iraq to oust Saddam Hussein . The Battalion was again deployed in 2004 to capture the city of Fallujah from insurgents ' control . In November 2004 , the Battalion , along with several other units , participated in Operation Phantom Fury ( also known as Al Fajr ( Dawn ) ) and was part of one of the biggest battles in Iraq to that time . On June 20 , 2006 , seven Marines and a Navy Corpsman of Kilo Company were charged with the April 26 , 2006 murder of disabled Iraqi civilian Hashim Ibrahim Awad , an event referred to as the " Hamdania incident " . All eight face additional charges of kidnapping , conspiracy , larceny , assault and housebreaking or unlawfully entering a dwelling . Five of the men are accused of making a false official statement . On May 19 , 2006 , Darkhorse Marines captured three insurgents responsible for the kidnapping and detention of Jill Carroll , an American journalist with the " Christian Science Monitor " . In June 2006 , 3 / 5 avenged the death of four Scout Snipers who belonged to 2 / 4 who had been killed on a roof top in Ramadi in 2004 . 3 / 5 ' s mission in Habbaniyah killed the insurgent sniper and driver of a vehicle . The sniper rifle was demilitarized and now resides at the 5th Marines Regimental Command Post . Afghanistan . Members of 3rd Battalion 5th Marines conducted operations in the Sangin District of Helmand Province , Afghanistan in support of Operation Enduring Freedom between September 2010 and April 2011 . The area was handed over by 3rd Battalion 7th Marines to 3rd Battalion 5th Marines . Twenty - five of the battalion ' s Marines were killed in action and 200 were wounded , many losing limbs . The 3rd Battalion are using Alternative Energy sources . A couple of forward combat bases use only solar power . One of the Marine foot patrols uses roll - up solar blankets to generate power for their radios and GPS . 3 / 5 was deployed as the Battalion Landing Team ( BLT ) for the 15th MEU . The 15th MEU is deployed with the Peleliu Amphibious Ready Group as a theater reserve and crisis response force throughout the U . S . Central Command and the U . S . 5th Fleet area of responsibility . Awards and Commendations . To date the battalion has seen eight members decorated with the Navy Cross , all for gallantry in combat . Two in Korea , five in Iraq , and the most recent one in Afghanistan awarded to Sgt Matthew T . Abbate . This is the most for any unit in the Marine Corps . Nickname Darkhorse . The battalion ' s nickname " Darkhorse " sprang from the radio call sign of its commander in Korea , Col Robert Taplett , who was known as Darkhorse Six . The name fell out of use until 2003 ; during the training to return to Iraq in 2004 the battalion ' s CO , Lt Col P J Malay requested use of the Darkhorse call sign as a homage to the Marines bravery in Korea ; this was approved by the Regimental Commander , Col Stewart Navarre . For the past ten years the nickname has stuck and the battalion now uses it on their unofficial patches .