Where America's Day Begins Island is the term for the island of Guam, which is located in the western Pacific Ocean. It is the largest and southernmost island in the Mariana Islands archipelago and is an organized, unincorporated territory of the United States. Guam is known for its tropical climate, beautiful beaches, and diverse culture. It is a popular tourist destination and has been nicknamed 'Where America's Day Begins' due to its location in the International Date Line.