The first U.S. Army formation established in Hawaii was the District of Hawaii, on 25 October 1910. It was succeeded on 1 October 1911, by the Department of Hawaii, and on 15 February 1913, by the Hawaiian Department. Brigadier General
Montgomery M. Macomb was the first commander of the Hawaiian Department. Headquartered in the Alexander Young Hotel, it moved to
Fort Shafter in 1921. The department also started wearing the red octagon insignia bearing the yellow letter "H." The colors symbolized Hawaiian royalty and the eight sides represented the main islands of Hawaii. Lieutenant General
Walter Short was commanding the Hawaiian Department in early December 1941, when the
Japanese attack on Pearl Harbor took place. He was quickly recalled to the mainland. To replace him, Lieutenant General
Delos Emmons was returned by General
Henry "Hap" Arnold to Hawaii as commanding general of the Department on December 17, 1941, ten days after the attacks. He encouraged the creation of the
Hawaii Defense Volunteers. He organized the replacement of the island's U.S. banknotes with new dollars
overprinted with the word
HAWAII; if the area were occupied, U.S. authorities could declare all marked dollars void and thereby render worthless all money which fell into enemy hands (by their capture of banks, businesses, etc.). He also requested
Army Air Forces Headquarters to send additional planes and received them as rapidly as possible. Emmons built up the forces in Hawaii, anticipating the
Battle of Midway. After Admiral
Chester Nimitz became Commander-in-Chief,
Pacific Ocean Areas in May 1942, the Hawaiian Department came under his command. On 26 May 1943, General
Robert C. Richardson Jr. arrived in Hawaii as the new commander of the Hawaiian Department. In July, he radically reorganized his command, placing the major air and ground forces in the area under seven major commands—all under his direct control. In recognition of the importance of shipping in an oceanic theater, he abolished the old Service Forces and created instead an Army Port and Service Command. A Hawaiian Artillery Command was also established, and a Department Reserve designated. All the combat divisions in the area, as well as those expected, were placed under separate command and a task force headquarters was formed in anticipation of future needs. Finally, Richardson appointed a deputy chief of staff for operations, who became, in effect, a War Plans officer. On 14 August, Richardson assumed the title Commanding General, U.S. Army Forces,
Central Pacific Area "by direction of the President." The geographical extent of General Richardson's authority under this directive, as distinguished from his command of the Hawaiian Department, corresponded to the area delineated as the Central Pacific in Nimitz' original directive. It encompassed all the land and sea areas of the Pacific between the
equator and the
42nd parallel, to the north (including
Canton Island), except for that portion of MacArthur's
South West Pacific Area that lay north of the equator and a small strip off the coast of
South America. Within this vast region—of which only a small portion was in American hands—Richardson had responsibility for administration and training of all U.S. Army troops, whether ground or air. This responsibility included also supply, but the precise nature of these duties was left undefined pending his recommendations. General Richardson had no responsibility for operations other than to assist "in the preparation and execution of plans" involving Army forces in the area, "subject to the direction of the Commander-in-Chief, Pacific Ocean Areas." In designating Richardson as Commanding General, U.S. Army Forces, Central Pacific Area, the
War Department said nothing about his duties as Hawaiian Department commander. His responsibilities for both were about the same, but the older command—which carried certain additional legal responsibilities—had been established by
Congress and could only be altered by that body. Did Richardson still retain those functions unique to the Hawaiian Department or had the new directive superseded the old? This confusion was quickly settled when the War Department on 18 September affirmed the continued existence of the Hawaiian Department under Richardson and stated explicitly what had been left implicit before—that its instructions to Richardson were not intended to affect the status of the Hawaiian Department.
Fort Shafter became a busy headquarters, and the barracks on Palm Circle were converted to offices. The major headquarters received the following names: U.S. Army Forces, Central Pacific Area (1943–44); U.S. Army Forces, Pacific Ocean Areas (1944–45); and U.S. Army Forces, Middle Pacific (1945–47). In 1944, the
Army Corps of Engineers erected the "Pineapple Pentagon" (buildings T-100, T-101, and T-102) in just 49 days. On 1 February 1947, the U.S. Army Forces, Middle Pacific became U.S. Army Pacific (USARPAC). During the
Korean War, USARPAC provided combat forces, training, and logistics. On 1 July 1957, USARPAC became a component of the
U.S. Pacific Command. In August 1990, WESTCOM was redesignated United States Army Pacific (USARPAC). On 1 October 2000, USARPAC reorganized into an
Army service component command. Since the
September 11 attacks, the command has played a major role in the
homeland defense of the United States. To fill operational gaps, the command sent soldiers to the
War in Afghanistan (2001–2021) and the
Iraq War (U.S. phase, 2003–2011). USARPAC has sent forces on multiple humanitarian missions, disaster relief, and
defense support of civil authorities. ==Commander's responsibilities==