The Guam Museum, operating under the Department of Chamorro Affairs, serves as the official national museum of the United States territory of Guam. Its primary mission is to preserve, promote, and perpetuate the unique history and cultural heritage of the Chamorro people, the indigenous inhabitants of the Mariana Islands.

The museum's permanent exhibition, "I Hinanao-ta Nu I Manaotao Tåno' I CHamoru Siha: The Journey of the CHamoru People," provides a comprehensive narrative of Guam's history from ancient times to the present day. This chronological journey covers the ancient latte period, the era of Spanish colonization beginning in the 16th century, the American administration following the 1898 Spanish-American War, the profound impact of the Japanese occupation during World War II, and the contemporary period leading to Guam's current political status.

Housed in a modern facility in the island's capital of Hagåtña, the institution functions as a vital cultural and educational center. It actively engages in archaeological research, artifact conservation, and the collection of oral histories to ensure the safeguarding of tangible and intangible cultural assets. The museum's collections include significant historical artifacts, archival photographs, documents, and contemporary artworks that reflect the island's layered identity.

Educational programming is a core component of the museum's work, offering lectures, workshops, and cultural demonstrations for residents and visitors. These programs often feature traditional Chamorro crafts, navigation techniques, language, and performing arts, fostering a deeper understanding of the living culture.

As a governmental entity, the museum also plays a role in advising on cultural policy and heritage management. Its establishment and ongoing operations underscore the importance placed on cultural sovereignty and historical awareness for the people of Guam, providing a central space where the island's complex past and dynamic present are interpreted and celebrated.