For the day visitor, one of Fire Island’s most interesting beaches is Sailors Haven, reached via ferry from Sayville. Sailors Haven is part wild beach and boardwalk, part dunes and grasses, and part Sunken Forest—a scrappy 300-year-old maritime forest located below sea level between two lines of sand dunes. A weathered gray boardwalk leads from the ferry dock through the 40-acre forest lush with oak, maple, red cedar, and sour gum trees, as well as sassafras, bayberry, inkberry, and cattail.

Due to the island’s strong winds and salty air, none of the trees can grow taller than the dunes, even though beneath their roots fresh water extends as deep as 40 yards. Essential to the forest’s existence, this fresh water occurs because the island’s annual rainfall exceeds its annual evaporation.

Run by the National Seashore, Sailors Haven is well equipped with bathhouses, a snack bar, and an interpretive center (631/597-6183 seasonal, 10 a.m.–4 p.m. Sat.–Sun. mid-May–mid-June, 10:30 a.m.–5 p.m. Mon.–Fri. and 10 a.m.–6:30 p.m. Sat.–Sun. late June–early Sept., check website for additional hours in May, Sept., and Oct., and Sunken Forest tours). Ferries operated by the Sayville Ferry Service (River Rd., Sayville, 631/589-8980, www.sayvilleferry.com, adults round-trip $14, children round-trip $6.50) run May–November.