Hillsdale is a city in the state of Michigan. As of the 2010 census, the city population was 8,305. It is the county seat of Hillsdale County, and is run as a council-manager government. The city is the home of Hillsdale College, a private liberal arts college noted for its academics and its influence in politics and education. In 2005, the town made history when Michael Sessions was elected mayor at age 18. He was still in high school at the time of his election.