The people of Guam are primarily Chamorro, although Guam also has a large percentage of Filipinos as well as Asian and Pacific Islanders. It is truly a melting pot of ethnicities, cultures and religions.
You will not find a more inviting, hospitable and patriotic group of people than the Chamorros. Perhaps it is because they personally experienced the wrath of the WWII, then saw the Americans come to their rescue, with many sailors and Marines paying the ultimate price to secure their freedom.
Guam was ceded to the US by Spain in 1898. Captured by the Japanese in 1941, it was retaken by the US three years later. The military installation on the island is one of the most strategically important US bases in the Pacific. (From CIA World Fact Book)