Guam Colonial Records

Spainish Colonization (1565-1898)
Guam was claimed by Spain in 1565. However, the island was not actually colonized until the 17th century. On June 21, 1898, the United States captured Guam during the Spanish–American War. By the Treaty of Paris, Spain officially ceded the island to the United States.

American Colonization (1898-Present)
On June 21, 1898, the United States captured Guam during the Spanish–American War. During World War II, Guam was invaded by the Imperial Japanese Army on December 8, 1941 shortly after the attack on Pearl Harbor. The Japanese military occupation of Guam lasted from 1941 to 1944. Guam was subsequently converted into a forward operations base for the U.S. Navy and Air Force. Guam's U.S. military installations remain among the most strategically vital in the Pacific Ocean. When the United States closed its Naval and Air Force bases in the Philippines after the expiration of their leases in the early 1990s, many of the forces stationed there were relocated to Guam.