M-3, known for most of its length as Gratiot Avenue, is a north–south state trunkline highway in the Detroit metropolitan area of the US state of Michigan. The trunkline starts in Downtown Detroit and runs through the city in a northeasterly direction along one of Detroit's five major avenues. The highway passes several historic landmarks and through a historic district. It also connects residential neighborhoods on the city's east side with suburbs in Macomb County and downtown.

Metro Detroit is a major metropolitan area in the U.S. state of Michigan, consisting of the city of Detroit and over 200 municipalities in the surrounding area with its largest employer being Oakland County. There are varied definitions of the area, including the official statistical areas designated by the Office of Management and Budget, a federal agency of the United States.