This essay tells the story of how Americans came to imagine Florida as islands and explains the cultural and political significance of Florida's geographic dispersal during the early national period, a time when efforts at national self-definition were largely rooted in a sense of America as solid ground where national and continental boundaries coincided. I argue that reflections on Florida in maps, settlers' guides, natural histories, and tales of Florida, such as "The Florida Pirate," reveal a largely overshadowed dimension of early national imaginations of self and national identity—namely, the prospect that mobility and dispersal could also sustain American character. The same people who pondered Federalist ideals of nationhood in documents such as the Northwest Ordinance and the Federalist Papers also contemplated popular images of Florida that challenged these ideals and proposed versions of America and Americans that might derive from impermanent, shifting ground.