High Quality Content by WIKIPEDIA articles! Lake Michigan–Huron (also Huron–Michigan) is the combined waters of Lake Michigan and Lake Huron, which are joined through the narrow, open-water Straits of Mackinac. They are sometimes considered a single lake because the flow of water through the straits keeps their water levels in near-equilibrium. Although the flow is generally eastward, the water moves in either direction depending on local conditions.