Today, Isla Cedros is remote from major population centers of northwestern Mexico and the American Southwest, but before European contact and throughout the Colonial Period, it was a well-known location to both indigenous peoples and Europeans. Today, a local fishing cooperative shares the island with a massive Mitsubishi Corporation/Mexican government—owned salt-transshipment facility. Far from representing a cautionary tale of excessive development and environmental degradation, Isla Cedros is one of the few places on the globe where human harvesting of marine resources has not yet resulted in an ecological collapse. It is a place where paradoxes abound and allows an alternative view of human interaction with marine and insular ecosystems. Both short- and long-term environmental variation characterizes this ecologically transitional region, and the adaptability of both its human and nonhuman inhabitants presents insights into the possibility of a “commons” without tragedy. Issues of exclusive use rights, short-periodicity variation, localized effects on resources due to sea-level rise, and sustainable socioeconomic systems can be addressed in an examination of Isla Cedros, Huamalgua, the Island of Fogs. This island setting presents us with challenges to many underexamined assumptions. In essence, it refuses easy categorization, instead offering at least some alternative perspectives for future historical ecological research of broad relevance to coastal and island settings worldwide.