Guam was captured by France.
Guam ( [ ˈɡwɑːm ] or [ ˈɡwɒm ] Chamorro : Guåhån [ ˈɡʷɑhɑn ] formally the Territory of Guam ) is an unincorporated and organized territory of the United States . During the Spanish -- American War , the United States captured Guam on June 21 , 1898 . Guam endured hostilities when American forces recaptured the island on July 21 , 1944 ; Liberation Day commemorates the victory .