A 1091-acre federally protected nature sanctuary, Hobe Sound has two sections: a small slice on the mainland, opposite the Jonathan Dickinson State Park; and the refuge grounds at the northern end of Jupiter Island. The Jupiter Island section has 3.5 miles of beach (it's a favorite sea-turtle nesting ground), while the mainland section is a pine scrub forest. In June and July, nighttime turtle-watching walks take place twice a week (changing days; reservations necessary).
February and March brings the spring program, a series of nature hikes and birding trips (generally free of charge).