The Green Mound is one of the best preserved and last remaining shell mounds in the region. The site holds a rich history of the prehistoric Florida Indians who inhabited the site for hundreds of years. Archaeological studies of the mound date artifacts to the St. Johns period (500 BC - 1565 AD). Mounds like this typically contain discards from daily life such as bones, shells, pottery, and tools. Archaeological studies of the mound show that people during the St. Johns I period (500 BC - 800 AD) occupied the site year round, while in the St. Johns II period (800 AD -1565 AD) people may have occupied the site seasonally. A botanical survey of Green Mound by John K. Small in 1922 revealed a unique botanical environment that included several rare plant species. Some of the plant species he noted are still visible in the area surrounding the mound, including wild-coffee, marlberry and snowberry. By 1933, a significant portion of the mound had been mined for shells used in road construction. In 1948, the Green Mound Historical Society, led by R.J. Longstreet, recognized the significance of the mound. The organization purchased it for preservation and turned it over to the Florida State Board of Forestry.