Green Mound in Ponce Inlet, Florida, is a large pre-Columbian shell mound and one of the largest shell middens in the United States. Built by Native Americans during the late St. Johns II period atop earlier St. Johns I remains, it preserves evidence of long occupation after 800 AD. Excavations showed it was a lived-in settlement, with clay floors, postholes, ash, fire pits, and hearths from structures made of local materials. Archaeologists believe its summit may have housed elite residents, including chiefs and religious leaders. Though once a prominent coastal landmark, Green Mound was heavily reduced by shell mining, road work, and erosion before later conservation and its 2020 National Register listing.