Mound Key developed over 2,000 years of the Calusa Indian civilization. The site likely began as a flat, mangrove-lined oyster bar that barely rose above the shallow waters of the Estero Bay. Located in the center of an estuary, food was easy to find. As the native population grew, the remains of their food were collected and heaped into middens. Mound Key is believed to have been the cultural center for the Calusa, who had their first encounters with Europeans in the early 1500s when the Spaniards were exploring the Caribbean and peninsula of Florida. With the Spaniards came diseases for which the natives had no immunity. Disease and warfare eventually brought an end to the Calusa around 1750.
Mound Key is the product of more than 2,000 years of Calusa Indian civilization. The site likely began as a flat mangrove-lined oyster bar that barely rose above the shallow waters of Estero Bay. Located in the center of an estuary, the island had easy access to food supplies. Estuaries are some of the most highly productive ecosystems making for rich and healthy habitats. As the native population grew, good remains were collected and heaped into middens. At its peak, the kingdom stretched from Tampa Bay down through the Ten Thousand Islands and eastward to Lake Okeechobee. The Calusa were known as the 'fierce people' and were said to have ruled over all the other tribes and trade networks throughout Florida. Mound Key is believed to have been their cultural center. The Calusa first encountered Europeans in the early 1500s when the Spanish were exploring the Caribbean and the Florida peninsula. In 1566, the King of the Calusa (Cacique) received the Spanish colonial governor at Mound Key. In 1567, the Jesuits founded a short-lived mission, San Anton de Carlos, on this site in an attempt to convert the Calusa. The mission was abandoned in 1569. While the Spanish introduced their culture, they also brought diseases to which the natives were not immune. Disease and warfare eventually brought an end to the Calusa civilization in the mid-1700s.
Several different styles of mounds were constructed by the Calusa, including ceremonial, household and burial mounds. Over the years, looting has caused extensive damage to the mounds. During an archaeological investigation carried out in 1994, a large number of looters¿ pits were discovered throughout the island. Years of public and scientific collection of surface items, such as decorated pottery shards and objects made of precious metals, has resulted in the removal of vast quantities of artifacts from the island. Historical materials from southwest Florida, collected during the 1890s, are maintained at the Smithsonian Institution and at the University of Pennsylvania Museum, catalogued simply as 'Punta Rassa.' It is likely that these artifacts came from Mound Key and were mailed from the Punta Rassa post office, accounting for the catalog assignment.
By the 1750s, the Calusa were gone, victims of warfare, slavery and disease. No one knows what happened to the Calusa residents of Mound Key or exactly when they left, but by the 18th century, the island was home to several Cuban fishing families who may have brought plants as well as their nets. Toward the end of the 19th century, American pioneers began to settle on the island. Most of these pioneers, like their Calusa and Cuban predecessors, made a living fishing and oystering. Some of the settlers were members of the Koreshan Unity, a turn-of-the-century communal society formed in Chicago. In 1894, led by their founder, Dr. Cyrus Teed, Koreshans established a utopian community by the Estero River. Eventually, they acquired portions of Mound Key, which sits at the mouth of the river. The Koreshans were very interested in planting crops of tropical fruits and nuts. Photographs show that the Koreshans had a banana plantation on Mound Key. Many Mound Key residents moved to the mainland after the devastating hurricanes of 1920 and 1926. In 1961, with their numbers dwindling, the last Koreshans donated their Mound Key property and some of their property in Estero to the state, so that a historical and archaeological park could be established.
As early as the 1700s, Spanish fisherman from Cuba had a small settlement on Mound Key. They used cisterns to collect rainwater for drinking and cooking as there was no fresh water available on the island. The remains of two cisterns are still found on the island. The Spanish settlers were displaced by American homesteaders who began inhabiting the island as early as 1866.
Mound Key is a beautiful place to study nature and observe pristine Calusa midden mounds. A half-mile trail traverses the island across several mounds and through mangroves and tropical hardwood hammock. There are no facilities on the island. There are two boat landings, one at each end of the trail. The main landing on the northwest side of the island is most suitable for powered watercraft. Both the main landing and the alternate landing on the southeast side of the island are suitable for canoes and kayaks. The estuarine waters surrounding the island are within the Estero Bay Aquatic Preserve and are an excellent place to catch both fresh and saltwater fish. Mound Key is accessible only by boat. Two nearby public boat launches are available at Koreshan State Historic Site and Lovers Key State Park.