51st state
Guam (formally the Territory of Guam) is an unincorporated and organized territory of the United States. Located in the western Pacific Ocean, Guam is one of five American territories with an established civilian government.
United States nationality law
All persons born in the island of Guam on or after April 11, 1899 (whether before or after August 1, 1950) subject to the jurisdiction of the United States, are declared to be citizens of the United States.