The largest of the islands, 9 miles east of Convoy Point, Elliott Key has a mile-long loop trail on the bay side at the north end of the campground. Boaters may dock at any of 36 slips (call ahead; Hurricane Sandy forced closure of the boardwalk and harbor in 2012, and at press time docks remained closed). Head out on your own to hike the 6-mile trail along so-called Spite Highway, a 225-foot-wide swath of green that developers mowed down in hopes of linking this key to the mainland. Luckily the federal government stepped in, and now it's a hiking trail through tropical hardwood hammock. Facilities include restrooms, picnic tables, fresh drinking water, cold (occasionally lukewarm) showers, grills, and a campground. Leashed pets are allowed in developed areas only, not on trails. A 30-foot-wide sandy shoreline about a mile north of the harbor on the west (bay) side of the key is the only one in the national park, and boaters like to anchor off here to swim. You can fish (check on license requirements) from the maintenance dock south of the harbor. The beach, fun for families, is for day use only; it has picnic areas and a short trail that cuts through the hammock.