The 15th century in North American history provides a timeline of events occurring within the present political boundaries of United States (including territories) from 1401 through 1500 in the Gregorian calendar. European explorers began to meet Native American societies--at least on Puerto Rico--during the final decade of the fifteenth century. To place developments in Native American (and Polynesian) societies in proper chronological order, we rely on reports of later explorers who encountered these societies.