Big Bay State Park is a state park of Wisconsin, United States, on Madeline Island, the largest of 22 Apostle Islands in Lake Superior. The 2,350-acre (951 ha) park has picturesque sandstone bluffs and caves and a 1.5-mile-long (2.4 km) sand beach. It encloses unique habitat types including lakeside dunes, sphagnum bogs, and old-growth forest. Bald eagles return annually to the park to nest and rear offspring.
The park, established in 1963, has picnic areas with tables, grills, water and toilets; a campground with drinking water, showers and toilets; an indoor camp for nonprofit groups; an outdoor group camp; and more than 9 miles (14 km) of trails, including nature trails. The park is open year-round, though winter visitation is mostly limited to hunters, snowshoers, and cross-country skiers.
All vehicles are required to purchase an admission pass, though pedestrians and bicyclists may enter free. To reach the park, visitors must take a 20-minute ferry ride from Bayfield, then travel approximately 5 miles (8.0 km) east on Highway H.