St. Clair, Lake, a lake between Michigan and Ontario, northeast of Detroit. It is 26 miles (42 km) long and 24 miles (39 km) wide. Although the lake is generally shallow, a navigation channel with a minimum depth of 27 feet (8 m) is maintained for oceangoing vessels. Lake St. Clair is connected to Lake Huron by the St. Clair River and to Lake Erie by the Detroit River, making it an important link in the Great Lakes-St. Lawrence Seaway system. Along the western shore are Grosse Pointe and other residential suburbs of Detroit.