Hunting Island State Park is a treat for running in South Carolina. It’s 50 miles from Hilton Head and 15 miles east of Beaufort. It’s a 5,000 state park, with a popular beach that attracts some 1 million annual visitors, and 8 miles of forested trails, passing by a lagoon. See the map below for more trail info. The park is a little over 2 miles from one end to the other. One highlight is the 1/4 mile Marsh Boardwalk Trail. There are many other activities in the park, such as fishing and other water related sports.
Note: Can be buggy in summer.