The southernmost of the Marianas is Guam, which is a 4-letter word in the crossword. Guam is an unincorporated and organized territory of the United States located in the western Pacific Ocean. It is the largest and southernmost island in the Mariana Islands archipelago. The island's capital is Hagåtña and the most populous city is Dededo. Guam has been a member of the United Nations since 1977.