Lake Huron is the second-largest Great Lake by surface area and third-largest by volume, with a retention period of approximately 20 years. By surface area, Lake Huron is the fifth-largest lake in the world. Lake Huron’s shoreline is the longest of any lake worldwide when including its 30,000 islands. Lake Huron also has the largest land drainage area among the Great Lakes. Saginaw Bay (1,070 square miles) and Georgian Bay (2,236 square miles) are the two largest bays on the Great Lakes. Saginaw Bay, Georgian Bay and the North Channel are home to some of the most high quality coastal habitat in the Great Lakes region.