This beautiful white sand beach is actually on the river side of the island. It's just next to the campground at Ft. Clinch. The Amelia River runs along the western side of the island, so this is looking north. If you gaze up the beach across the northern tip of the island, you're looking across the Cumberland Sound between Amelia Island and Cumberland Island, Georgia. The sandy beach that you see across the way is Cumberland Island. It's quite common to see the wild horses hanging out on that beach, as well.
Just around the bend on this Amelia Island beach is the actual fort (Ft. Clinch), right where it should be to defend the island. And, right in front of that is where the nuclear subs from King's Bay (Georgia) turn around. The water is quite deep in the Cumberland Sound; it's a natural turning basin for the subs doing maneuvers. From the northern tip of Amelia Island, you can see the submarine hangars in the distance. Amazingly large.