evidence: - Wake Island (Pacific) [...] Guam became a U.S. territory in 1898 after it was also ceded to the U.S. in the aftermath of the Spanish-American War. It is often called the place where "America Starts its Day" because it’s located on the other side of the International Date Line. [...] Yes. Guam is a U.S. Territory. It has been a territory of the United States since 1898, since it was ceded to the U.S. by Spain in the Treaty of Paris.