St. Clair County
St. Clair County is a county located in the U. S. state of Michigan bordering the west bank of the St. Clair River. As of the 2010 census, the population was 163,040. It is the 13th-most populous county in the state. The county seat is Port Huron, located at the north end of the St. Clair River at Lake Huron.