Mound Key Archeological State Park

Mound Key is an archaeological site on a shell-built island in Estero Bay with about 50 acres of land. The grounds feature several mounds and ridges rising up to 30 feet (9 meters) above the water, surrounded by mangrove forest.

The Calusa people built this complex settlement roughly 2000 years ago as their capital called Calos, complete with water routes and canal systems. Spanish colonizers established an early mission here in 1566 but abandoned it after a short time.

The site shows how the Calusa people relied on the sea and gathered food from shells, fish, and other marine resources, visible in the shell and bone remains scattered throughout. These traces reveal a society deeply connected to coastal life and skilled at using their surroundings.

The island is only reachable by boat since no direct land connection exists, with launches available from Koreshan or Lovers Key state parks. Visitors should expect humid conditions, mosquitoes, and uneven ground, so sturdy shoes and insect repellent are recommended.

The island was partly built by human hands, as the Calusa deliberately stacked shells to create their structures and raised areas. This is one of the few places in North America where artificially made islands from an early civilization remain intact.