IMCOM-Pacific, headquartered at Fort Shafter on the island of Oahu, Hawaii, oversees 11 U.S. Army Garrisons and one joint base Army Support Activity, supporting nearly 300,000 U.S. military-affiliated personnel at more than 125 installation sites in four countries –  the United States, Japan, the Republic of Korea and the Republic of the Marshall Islands – spanning 20 million square miles, an area six times larger than the Continental United States.