Although the exact location of the fort erected by the British in 1736 remains uncertain, the island still bears its name. In pre-WWII glory days, flappers flocked here to the ritzy Ribault Club, built in 1928, for lavish Gatsby-esque bashes. Now housing the visitor center (9am to 5pm Wednesday to Sunday), the meticulously restored mansion flaunts grand archways and three dozen French doors. It's the starting point of the 4.4-mile Saturiwa loop trail, which you can walk, bike or drive.
Enormous shell middens date the island's habitation by the Timucuan tribespeople to over 4000 years ago.