Guam, an island at the southern tip of the Mariana Islands in the Western Pacific, is at 13°26 'north latitude and 144°43' east longitude. It covers an area of 541 square kilometers. Magellan arrived in Guam in 1521 while traveling around the world. On March 6, the indigenous Chamorro people of Guam discovered Magellan, the great navigator, on the coast, only breathing. Magellan returned to Spain after several months of experience on the island, followed by his return to the Chamorro people of Guam who had saved his life and provided him with supplies-300 years of Spanish occupation and rule. In the next 100 years, Americans and Japanese fought to seize this territory until 1944, when the United States declared Guam a non-incorporated territory. The United States captured Guam from Spain in the Spanish-American War in 1898. During World War II, Guam was once the seat of the U.S. Pacific Fleet Command. It was occupied by the Japanese on December 11, 1941 and retaken by the U.S. military on July 21, 1944. In 1950, the United States passed a bill declaring the island an "unincorporated territory" of the United States and giving local powers to the Guam Autonomous Government and placing it under the jurisdiction of the U.S. Department of the Interior.

The Guam base has always occupied a very important position in the Western Pacific military base system. During the Korean War and Vietnam War, Guam, as an important strategic naval and air base, played an important role in gathering troops, transporting ammunition and materials, and supporting long-range bombings.