The Ten Thousand Islands is the coastal area in the Everglades National Park where mangrove islands and shallow creeks make a wilderness maze. Some of the islands are landmasses called keys but many are clumps of mangrove trees rising out of coral reefs, oyster beds, and sandy shoals. The area lies southeast of Naples and northwest of the Everglades National Park. The many islands form a transition from the freshwater marsh of the "river of grass" to the open salt water of the Gulf of Mexico.
Marco Island is the largest of Florida's Ten Thousand Islands, located on the Gulf of Mexico in Southwest Florida. 