Cadillac is a city in and county seat of Wexford County in the U.S. state of Michigan. The population was 10,371 at the 2020 census, which rank…Cadillac is a city in and county seat of Wexford County in the U.S. state of Michigan. The population was 10,371 at the 2020 census, which ranks it the third most-populated city in the Northern Michigan region after Traverse City and Alpena.