The Saint Clair River flows approximately 40 miles in a southerly direction from the outflow of Lake Huron to Lake Saint Clair. From Lake Huron to Lake Saint Clair, the water level falls about five feet. The Saint Clair River has three distinct reaches, including the Saint Clair Flats delta. Nearly all of the river is favored by ship spotting enthusiasts.
The upper river begins at the southern end of Lake Huron. Along the western side are Fort Gratiot Light and Port Huron Coast Guard Station. Point Edward Front Range Lighthouse marks the river’s head on the Canadian side of the river.
The upper reach, extending downstream from Lake Huron to a point about three miles below the International Blue Water Bridge, is about 800 feet wide at its narrowest point. Mid-channel depths in the upper reach vary from about 30 to 70 feet. Maximum currents of the Saint Clair River occur near the Blue Water Bridge.
The Blue Water Bridge (BWB) is a major international crossing over the Saint Clair River. Located between Port Huron, Michigan, and Point Edward, Ontario, the bridge is an important connection between the Midwestern U.S. and Ontario, Canada.
Below the Blue Water Bridge, in the City of Sarnia, Ontario, a sprawling industrial waterfront dominates the river. Meandering along the river are several scenic parks, trails, and other recreational areas.
The middle reach of the Saint Clair extends downstream for approximately the next 27 miles, is about one-half mile wide and has channel depths varying from 27 to 50 feet.
Located in the middle reach are Stag and Fawn Islands. Near the City of St. Clair, Michigan, the middle ground shoals are a hazard to boaters.
South of Stag Island, the City of St. Clair is known for having the longest freshwater boardwalk in the world. Along the riverfront, Palmer Park is a spectacular location to view freighters up close.
Along the banks of the middle Saint Clair River are residential neighborhoods, waterfront businesses, and public spaces.
Prior to entering Lake Saint Clair, the river divides into several channels creating an extensive delta known as the Saint Clair Delta or Saint Clair Flats.
The largest river delta system in the world, the Saint Clair Flats include important habitats for fish and wildlife.
In 1985, the International Joint Commission (IJC) identified the Saint Clair River as an Area of Concern (AOC) in the Great Lakes Basin as it did not meet the objectives of the Great Lakes Water Quality Agreement.
The Saint Clair River is one of only 5 bi-national AOCs. A collaborative effort between the United States and Canada seeks to delist the river as an AOC after all recommended actions have been completed on both sides of the river.
The Saint Clair River is home to the largest remaining spawning populations of Lake Sturgeon in the Great Lakes region.
A number of natural limestone reefs and rocky spawning habitats were destroyed in the river during the construction of shipping channels.
To restore spawning habitat for lake sturgeon and other native species, three fish spawning reefs were installed in three locations throughout the Saint Clair: Middle Channel reef, Harts Light reef, and Pointe aux Chenes reef.
The invasive round goby was first seen in North America in 1990 in the Saint Clair River. Carried by ballast waters from ocean-going vessels, these small fish quickly spread through the Great Lakes and the St. Lawrence River.