The Chamorro (also CHamoru) people are the indigenous inhabitants of the Mariana Islands, politically divided between the United States Territory of Guam and the encompassing Commonwealth of the Northern Mariana Islands in Micronesia. The CHamorus are primarily of Austronesian descent and some are also descendants of Japan. Due to the Spanish colonization of the islands, many also have Spanish ancestry. CHamorus and other Micronesians constitute about half the current population of Guam.

Significant CHamoru populations also exist throughout the United States. According to the 2000 US Census, about 64,590 people of CHamoru ancestry live in Guam and another 19,000 live in the Northern Marianas. An estimated 93,000 live outside the Marianas primarily in Hawaii and along the West Coast of the United States, all of which together are designated as Pacific Islander Americans according to the US Census.

Precolonial society in the Mariana Islands was based on a caste system, Chamori being the name of the ruling, highest caste.

After Spain annexed and colonized the Mariana Islands, the caste system eventually became extinct under Spanish rule, and all the indigenous residents of the archipelago eventually came to be referred to by the Spanish exonym Chamorro. The name CHamoru is an endonym derived from the indigenous orthography of the Spanish exonym. The digraph ch is treated as a single letter, hence both characters are capitalized at the beginning of a sentence or proper noun, much like ij in Dutch.

Some people theorize that Spanish definitions of the word CHamoru played a role in its being used to refer to the island’s indigenous inhabitants. Not only is “Chamorro” a Spanish surname; it also has other meanings in Spanish.

The spelling of the word “CHamoru” has long been debated, and you will see many variations in written accounts, including “Tsamoru,” “Chamorru,” and the more popular “Chamorro;” however, Chamorro institutions on Guam advocate for the spelling CHamoru, as reflected in the 2017 Guam public law 33-236. In 2018, the Kumision I Fino’ CHamoru (the Commission on the CHamoru Language) and the Teaching of the History and Culture of the Indigenous People of Guam) announced CHamoru as the preferred standardized spelling of the language and people, as opposed to the conventional spelling Chamorro, which we have chosen to use in the naming of our foundation and will use throughout this site.