A State Historical Building, the Grand Hotel features 385 guest rooms, four Har Tru-based clay courts, 18 holes of golf, the heated Esther Williams Swimming Pool, bicycle rentals, an exercise facility, a half-mile outdoor exercise course, the Grand Hotel Spa, children's programs, specialty shops, meeting space and the world's longest front porch at 660 feet. Mackinac Island is accessible only by boat or plane.