First as a colonial American, and later as a patriot of outstanding importance, Benjamin Franklin (1706–1790) maintained a now little-known interest in geological questions. He began as a follower of the English theorists Burnet, Woodward, and Whiston but soon assimilated some of their ideas with original observations and speculations. Though long attentive to earthquakes and their possible causes, Franklin learned from interactions with other naturalists to broaden the range of his theorizing. Eventually, his earth science topics included the origin of springs and rivers, the Flood and the Abyss, natural convulsions of great power, strata and their distortions, the age of Earth, the nature of its core, the origin of mountains, the history of life, and the problem of extinction. Through his championing of American phenomena and thought, he not only contributed to the work of European savants but significantly enhanced our national presence and its prestige. Yet, if remembered in the history of American geology at all, Franklin has received far less attention than his accomplishments and influence deserve. Even those who purport to write on him and science too often neglect his theorizing about Earth. Though Franklin is appropriately remembered as a physicist, inventor, diplomat, author, and printer, we have apparently forgotten that, for more than sixty years, he maintained an active interest in the physical geography, dynamics, and history of our planet. America’s longtime intellectual leader in those fields as in others, Franklin was regarded worldwide as a significant geological philosopher.