Lake Saint Clair, together with the St. Clair River on the north and the Detroit River on the south, forms a waterway connecting Lakes Huron and Erie. Lake St. Clair has been dredged so that large ships can cross it. Roughly heart-shaped, the lake is 25 miles (40 kilometers) across at the center and covers an area of 460 square miles (1,191 square kilometers). It forms part of the boundary between the state of Michigan and the province of Ontario.