Big Mound City is a prehistoric archaeological complex in southeastern Florida within the Lake Okeechobee Basin, dating to Glades period III around 1000 AD. One of four recognized monumental Native American earthwork complexes in the basin, it consists of at least nine mounds, a ridge system, radiating causeways, and crescent-shaped man-made ponds rather than a single mound. Some mounds served as burials, indicating both ceremonial and inhabited use. Although little excavated and only briefly studied in the 1930s, it has remained important in south Florida archaeology and is linked to the same mound-building tradition as Tony's Mound, Fort Center, and Ortona Prehistoric Village.