Guam's population is around 160,000, but the island feels larger than that — it has the density and the traffic of a real city, especially in the Tamuning-Tumon corridor. The indigenous Chamorro people make up roughly 37% of the population. Filipinos are the next largest group at about 26%, followed by white Americans (mostly military and their families, who add another 30,000 or so to the de facto population), and smaller communities of Chuukese, Korean, and Chinese residents.
The Chamorro have been here for at least 3,500 years, arriving as expert seafarers from Southeast Asia. Three centuries of Spanish colonialism (from 1668), followed by American rule from 1898, Japanese occupation during World War II, and then US territory status since 1944 have shaped a culture that is genuinely its own — Catholic but not Spanish, American but not mainland, Pacific but distinct from Polynesia.
Chamorro is still spoken, particularly among older residents and in cultural contexts, though English is the everyday language of business, school, and government. You'll hear a mix on the street. Learning a few words — håfa adai (hello), si yu'us ma'åse' (thank you) — will earn you genuine warmth.
The military presence is large and unavoidable: about 27% of the island is occupied by US military bases. It's a fact of life here, economically important and politically complex. Chamorros have no voting representation in the US Congress and cannot vote for president, which fuels an ongoing, often quiet conversation about self-determination. Don't be surprised if locals bring it up — they're generally happy to talk about it.