3rd Battalion 25th Marines 3rd Battalion , 25th Marines ( 3 / 25 ) is a reserve infantry battalion in the United States Marine Corps . The battalion was first formed in 1943 for service in the Pacific Theater of Operations during World War II , taking part in a number of significant battles including those at Saipan and Iwo Jima before being deactivated at the end of the war . In the early 1960s , the unit was reactivated as a reserve battalion . Currently headquartered in Brook Park , Ohio with units throughout Ohio , New York , and Pennsylvania , the battalion is nicknamed " three deuce five " and consists of approximately 800 Marines and Sailors . They fall under the 25th Marine Regiment and the 4th Marine Division . Recent operations have included tours in Iraq and Afghanistan . Mission . To locate , close with , and destroy the enemy by fire and maneuver or to repel the enemy assault by fire and close combat . Additionally , the Battalion is prepared to augment active Marine Forces in case of national emergency . History . World War II . The 25th Marine Regiment was activated on May 1 , 1943 . The 25th Marine Regiment fought in the Battles of Saipan , Tinian , Kwajalein Atoll , and the Iwo Jima . During the fighting on Iwo Jima , the battalion was tasked with the securing of Airfield One , before pushing northward into the heart of the Japanese defenses . Colonel Justice M . Chambers received the Medal of Honor for his actions as 3 / 25 ' s commanding officer during the battle . His citation reads , in part , that while " exposed to relentless fire , he coolly reorganized his battle - weary men , inspiring them to heroic efforts by his own valor and in leading an attack on the critical , impregnable high ground . " His medals are displayed in the trophy case located at H & S Brook Park , Ohio . In 1945 the regiment was deactivated when World War II had ended . Reactivation : 1960s – 1990s . On July 1 , 1962 , the 25th Marine Regiment was reactivated as a Marine Corps Reserve Unit . This Regiment has continued to train in " every clime and place " for its role in the defense of the United States . The 3rd Battalion , 25th Marines was again activated during Operation Desert Storm to support operations conducted in Southwest Asia . Although the Marines of 3 / 25 did not deploy to Southwest Asia , they played a key role in other operations in Norway , Panama , and Honduras . Global War on Terror . The battalion was activated on January 4 , 2005 . From January 10 to late February 2005 , the companies conducted pre - deployment training at Marine Corps Air Ground Combat Center Twentynine Palms and March Air Reserve Base , California . The battalion was in Iraq by the first week of March 2005 , tasked with training the Iraqi Security Forces ( ISF ) and conducting stability and security operations to prevent insurgents from gaining a foothold in and around the cities of Iraq ' s Al Anbar province . Major operations that the battalion participated in during its deployment included Operations Matador , New Market , Spear , Sword , River Bridge , Outer Banks , and Quick Strike . The battalion rotated out of Iraq in late September 2005 , and deactivated on January 3 , 2006 . Forty - six Marines and two Navy Corpsmen serving with the battalion in Iraq were killed in action . A memorial paying tribute to them was erected at the Battalion headquarters in Brook Park , Ohio and was dedicated on November 12 , 2005 . In August 2010 , 3 / 25 deployed to Afghanistan in support of Operation Enduring Freedom . The battalion ' s missions were across Helmand province and included reconnaissance , civil affairs , security and combat operations . The battalion rotated out of Afghanistan in March 2011 , and was deactivated in June 2011 . One Marine serving in the battalion was killed in action during the deployment .