Detroit  is the most populous city in the U.S. state of Michigan, the fourth-largest city in the Midwest and the largest city on the United States–Canada border. It is the seat of Wayne County, the most populous county in the state.

The municipality of Detroit had a 2015 estimated population of 677,116, making it the 21st-most populous city in the United States. The metropolitan area, known as Metro Detroit, is home to 4.3 million people and lies at the heart of the Great Lakes Megalopolis area, with around 60 million people.

Roughly one-half of Michigan's population lives in Metro Detroit alone. The Detroit–Windsor area, a commercial link straddling the Canada–U.S. border, has a total population of about 5.7 million.

Sourse: wikipedia