Horn Island is an island in the Gulf Islands National Seashore that is accessible only via private boat. The island, which is among the few undeveloped barrier islands on the Gulf Coast, was designated by Congress as a wilderness area in 1978. Wildlife on the island includes uncommon species of birds, animals, and marine life. Popular activities on the island include swimmingsnorkeling, fishing, hiking, beach combing, bird watching, boating, and camping.