The area was first inhabited over 7,000 years ago by natives drawn by the warm mineral spring. The hydrological spring of the same name, locally known as the "Original Fountain of Youth", attracted guests in the 19th century; more than a dozen hotels were near the spring. Today, the sulfur-scented spring water feeds an adjacent public swimming pool before flowing the short distance to the St. Johns River. The Green Cove Springs area was first developed by George J. F. Clarke in 1816 when he was provided land, under a Spanish land grant, to build a sawmill. Green Cove Springs was established in 1854 as White Sulfur Springs. Renamed in 1866, it became the Clay County seat in 1871.