The Fort Gratiot Lighthouse is located at the mouth of the St. Clair River along the shores of Lake Huron. It is the oldest existing lighthouse in Michigan and still serves as a Coast Guard post. The light is located on the north side of the Blue Water Bridge. There is a park next to the facility that allows unobstructed view. Beware of heightened security and do not try to enter the Coast Guard facility. On a scale of 1 to 5 stars, we give it 3.5 stars.