Guam is an organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. It is the westernmost point and territory of the United States; in Oceania, it is the largest and southernmost of the Mariana Islands and the largest island in Micronesia. Guam's capital is Hagåtña, and the most populous city is Dededo.

People born in Guam are American citizens by birth. Indigenous Guamanians are the CHamoru, historically known as the Chamorro, who are related to the Austronesian peoples of Indonesia, the Philippines, Taiwan, Micronesia, and Polynesia. As of 2021, Guam's population is 168,801. CHamorus are the largest ethnic group, but a minority on the multiethnic island. The territory spans 210 square miles (540 km2; 130,000 acres) and has a population density of 775 per square mile (299/km2).