Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. St. Clair County is a county in the U.S. state of Michigan. As of the 2000 census, the population was 164,235, with the 2008 Census Bureau estimate placing the population at 168,894. According to the U.S. Census Bureau, it forms part of the Metro Detroit area. Geographically, it lies in the Thumb area of Michigan. The county seat is Port Huron. The county was created 10 September 1820 and its government was organized in 1821. Being situated on the western shores of Lake Saint Clair, the county''s name is taken from the lake. An expedition led by the French explorer René Robert Cavelier, Sieur de La Salle named it Lac Sainte-Claire, because they entered the lake on August 12, 1679, the feast day of Saint Clare of Assisi.