The capture of Guam by the United States during the Spanish-American War in 1898 marked the beginning of American rule over the island, which would last for over a century[1][2][3]. The U.S. Navy governed Guam from 1898 until 1950, with a brief interruption when the island was occupied by Japan during World War II[1][3].

In the immediate aftermath of the capture, Captain Henry Glass entrusted the governance of Guam to a small contingent of American troops and a naturalized American citizen named Francisco Portusach[4]. However, Portusach's role was more of a balancing power with the Spanish treasurer José Sixto, rather than a formal governorship[2].

The period of political ambiguity ended in August 1899 when Captain Richard Leary became the first naval governor of Guam, establishing the first naval administration[2][4]. Under U.S. rule, Guam underwent significant changes, including the adoption of American systems of governance, language, and culture[1].

The naval governors made many contributions to the island, though their rule was not without controversy[1]. The U.S. Navy's governance had long-lasting impacts on Guam, including the construction of infrastructure, the rebuilding of the capital Hagåtña based on a California model, and the establishment of large military bases that still dominate much of the island today[1].

Sources [1] US Naval Era Governors: Contributions and Controversies https://www.guampedia.com/us-naval-era-governors-contributions-and-controversies/ [2] U.S. Capture of Guam - Naval History and Heritage Command https://www.history.navy.mil/browse-by-topic/wars-conflicts-and-operations/spanish-american-war/us-capture-of-guam.html [3] Guam History - FamilySearch https://www.familysearch.org/en/wiki/Guam_History [4] Capture of Guam - Naval History and Heritage Command https://www.history.navy.mil/research/publications/documentary-histories/united-states-navy-s/the-capture-of-guam.html [5] [PDF] Assessment of Self-Governance Sufficiency https://decol.guam.gov/sites/default/files/giha-mona-sd-study_part-i-digital.pdf