Guam (i/ˈɡwɑːm/ or /ˈɡwɒm/; Chamorro: Guåhån;[needs IPA] formally the Territory of Guam) is an unincorporated and organized territory of the United States. Located in the northwestern Pacific Ocean, Guam is one of five American territories with an established civilian government. The capital city is Hagåtña, and the most populous city is Dededo. In 2015, 161,785 people resided on Guam. Guamanians are American citizens by birth. Guam has an area of 544 km2 (210 sq mi) and a density of 297/km² (770/sq mi). It is the largest and southernmost of the Mariana Islands, and the largest island in Micronesia. Among its municipalities, Mongmong-Toto-Maite has the highest density at 1,425/km² (3,691/sq mi), whereas Inarajan and Umatac have the lowest density at 47/km² (119/sq mi). The highest point is Mount Lamlam at 406 meters (1,332 ft) above sea level.

What country is Guam a territory of?