Wayne County is the most populous county in the U.S. state of Michigan. As of the 2010 census, its population was 1,820,584, making it the 19th-most populous county in the United States. The 2014 Census update listed the county's population at 1,764,804. The county seat is Detroit, the most populous city in Michigan and 18th-most populous city in the United States. The county was founded in 1796 and organized in 1815.