There are two islands known as Bois Blanc in North America:

• One is coterminus with Bois Blanc Township, Mackinac County in the U.S. state of Michigan. The island is about 12 miles (19 km) long, 4 miles (6.4 km) wide in Lake Huron southwest of Mackinac Island and almost due north of the city of Cheboygan. The community of Pointe Aux Pins is on the south side and has ferry service to Cheboygan, Mackinac Island, and Round Island. In winter a safe path over the ice is marked by discarded Christmas trees allowing islanders to drive over to the mainland.

• The second island, about 2 miles (3 km) long, is in the Canadian province of Ontario in the Detroit River directly west of Amherstburg, Ontario. Also known as Boblo Island due to the Boblo mining company which owned the island for years. It was formerly the home of the Boblo Amusement Park, which closed around 1995 and is currently a private "resort" island in receivership due to unpaid bills to many creditors, including the Town of Amherstburg. The main shipping channel of the St. Lawrence Seaway (currently for north-bound ships) lies between Bois Blanc Island and the Amherstburg mainland. Fort Amherstburg (now Fort Malden ) was built in 1796 to replace Detroit for the British. Guns from the fort could reach the island, hence secure the Detroit River. The island is served by a private ferry.