Winyah Bay is a coastal estuary that is the confluence of the Waccamaw River, the Pee Dee River, the Black River, and the Sampit River in Georgetown County, in eastern South Carolina. Its name comes from the Winyah people, who inhabited the region during the eighteenth century. The historic port city of Georgetown is located on the bay, and the bay generally serves as the terminating point for the Grand Strand.
The bay is evidence of a drowned coastline, created by a rise in sea level in recent geologic time. It was a prime site for fishing by generations of Native American cultures. This area was developed by English colonists as a seaport and center of rice culture and timbering.