Sandusky is the most populous city and county seat of Sanilac County, Michigan. The population was 2,679 at the 2010 census. Sandusky i…Sandusky is the most populous city and county seat of Sanilac County, Michigan. The population was 2,679 at the 2010 census. Sandusky is served by Sandusky Community Schools. The district has an elementary school and a junior/senior high school. Sandusky is home to the Wolves, who usually play sports in the Greater Thumb East Conference. Sandusky is a Division 3 school.