The Big Bay sloop is an unidentified shipwreck in Lake Superior off Madeline Island near La Pointe, Wisconsin. Discovered east of Big Bay State Park in the 1990s, it preserves the remains of a sunken sloop now recognized as an archaeological site. Because small Great Lakes craft were often poorly documented, its exact identity is unknown, though wire rigging and a metal cleat suggest it dates from about 1880 to 1920 and likely served as a merchant vessel. It is significant as the only known shipwreck of its kind in Wisconsin waters and was listed on the National Register of Historic Places on January 14, 2009, while also designated a National Marine Protected Area.