The 17th Defense Battalion landed on Tinian on August 2, 1944.  The battalion immediately established anti-aircraft positions north of the airfield and in the harbor.  The battalion remained on occupation duty on Tinian for the next year.  During these months they conducted routine patrols and took a number of Japanese prisoners of war still on the island after the battle. Three Japanese aircraft bombed and strafed the island on November 3, 1944 however the battalion's batteries were not able to successfully engage any of the aircraft.  The battalion was guarding the airfield on August 6, 1945 when the Enola Gay launched to drop the first ever nuclear weapon against Hiroshima in mainland Japan.  On August 15, 1945 the 17th Antiaircraft Artillery Battalion was relieved of its tactical duties on Tinian.  It finally departed the island on November 1, 1945 on the USS Griggs (APA-110).   The battalion sailed back to the United States and was officially decommissioned on December 6, 1945 at Marine Corps Base Camp Pendleton, California.