Off the Maryland coast, the 37 mile Assateague Island has a great out and back hiking trail among the dunes and surf. Keep an eye out for dolphins and wild ponies. There are nice campsits among the pines. Park at the Ranger Office on SR611 about 9 miles from US50.
Overall, Assateague Island National Seashore is the 4th most popular hiking trail of all 20 hikes in Maryland.