Flat Rock is a city in Wayne and Monroe counties in the U.S. state of Michigan. A Downriver suburb of Detroit, Flat Rock is located roughly 23 miles southwest of downtown Detroit. At the 2020 census,

Wayne County is the most populous county in the U.S. state of Michigan. As of 2020, the United States census placed its population at 1,793,561, making it the 19th-most populous county in the United S