Home : Our Story : Our History

124 years of U.S. Army contributions in the Indo-Pacific underscore the role of the American Soldier, landpower’s significance, and the Army’s war-and-peace legacy in this joint theater.

The U.S. Army's story in the Indo-Pacific has been characterized by growth and expansion, not just in manpower and geography, but also responsibilities, roles, and missions.


 The Army's presence in the Indo-Pacific was born out of great power conflict among declining European colonial powers, coupled with rising Chinese and Japanese rivalries. 
Spain’s defeat and the U.S. annexation of the Philippines required forward military presence from the United States in the region.


During the China Relief Expedition of 1900, the U.S. Army sent forces as part of an international coalition into China to rescue American citizens and other foreign nationals during the Boxer Rebellion. Subsequently, the U.S. Army established forward staging bases in Japan from which to operate on the Asian continent.


The Army and Navy jointly decided to make Pearl Harbor the principal American Naval base in the Pacific in 1907. Doing so strengthened the U.S. Army's presence in the region and led to the establishment of a headquarters at Fort Shafter. In 1913, U.S. Army Pacific's forerunner, the Hawaiian Department became an independent command under the War Department. 

Indo-Pacific-based Soldiers deployed to crises in the Pacific – the Philippines (1905-16) and Russian Siberia (1918-20) – to provide stability and protect American citizens and interests. Land forces continued to establish bases throughout the region and conduct contingency operations abroad. 
The U.S. Army’s experience in the Asiatic-Pacific Theater during World War II highlights Army roles and the enduring value of landpower in the Indo-Pacific. The Army’s 3 Field Armies, 6 Corps, and 21 Divisions fought 24 campaigns in the Indo-Pacific - it fought 19 campaigns in Europe, Africa, and the Middle East combined. In every campaign, Soldiers fought alongside Sailors, Marines, Airmen, and Allies, including British Commonwealth troops, Indian and Malayan units, Aussies, Kiwis, Dutch, Filipinos, and Chinese. The U.S. Army supported an enormously complex joint multinational force, contributing to victories like the Battle of Midway and on Guadalcanal.

Army support underpinned the massive buildup and movement of personnel and war materiel. After 7 December 1941, Hawai’i expanded as the strategic hub to coordinate U.S. resources for the Pacific Front. To meet wartime demands, the Hawaiian Department evolved into a Theater Army (eventually known as USARPAC). Alongside British Commonwealth Allies, the Army transformed Australia into a vast forward logistics node, supply base, and training area, to enable offensive Allied thrusts in Oceania and the Western Pacific. The Army supported all forces in South Asia with foundational capabilities, including troop life support, overland transportation, communications, intelligence, forward medical, evacuation, and rear-area health care. Support was often buttressed by – or reliant on – local populations, as in Papua and Java. Military construction and engineering support built thousands of miles of roads, and hundreds of bridges, warehouse, airfields, and port facilities. Army leaders exercised extensive command and control. Tenth Army – formed to oversee the invasion of Formosa (now Taiwan) – commanded a tactical air command and Army & Marine corps- sized elements during the Okinawa campaign.

The Theater Army resourced, trained, and sustained forces on the Korean Peninsula while Army forces fought as part of a combined coalition during the Korean War. Since Armistice, thousands of U.S. Army forces remain on the Peninsula, preserving peace alongside the Republic of Korea Army.

The Theater Army provided trained combat forces, intra-theater sustainment, and logistical support for U.S. forces in the Vietnam War.

In the late 1980s, near the end of the Cold War, the U.S. Army temporarily renamed USARPAC as the U.S. Army Western Command (WESTCOM), adding U.S. Army Alaska in 1989 and U.S. Army Japan in 1990 as subordinate commands. During this time, the Theater Army focused on engagement strategies with Allies and partners under the Joint Force's theater security cooperation program.

The Theater Army deployed global peacekeeping forces to the Sinai Peninsula, Haiti, East Timor and Bosnia and increasingly supported humanitarian assistance and disaster relief missions throughout the Indo-Pacific.

In the two decades following the 9/11 terrorist attacks, USARPAC supported counterterrorism and counterinsurgency operations worldwide with tactical unit deployments to the Middle East and Central Asia in support of the Global War on Terrorism.

In response to the global pandemic, USARPAC was designated a TJFLCC and coordinated with joint and interagency partners to provide support to Americans, Allies, and Partners.