The Detroit metropolitan area, often referred to as Metro Detroit, is the metropolitan area located in Southeast Michigan centered on the city of Detroit which shares an international border with Windsor, Ontario. The Detroit metropolitan area is the second largest U.S. metropolitan area connecting the Great Lakes system to the Saint Lawrence Seaway. As a major metropolitan area, it is known for its automotive heritage, arts, entertainment, and popular music and sports legacies. The area includes a variety of natural landscapes, parks, and beaches with a recreational coastline linking the Great Lakes.

The Detroit Urban Area, which serves as the core of the Metropolitan Statistical Area, ranks as the 12th most populous of the United States, with a population of 3,734,090 as of the 2010 census, and an area of 1,337.16 square miles (3,463.2 km²). This urbanized area covers parts of the counties of Wayne, Oakland, and Macomb. These counties are sometimes referred to informally as the Detroit Tri-County Area, and had a population of 3,863,888 as of the 2010 census with an area of 1,967.1 square miles (5,095 km²).

Detroit ( /diˈtrɔɪt/) is the largest city in the U.S. state of Michigan, and the seat of Wayne County. It is the major city among the primary cultural, financial, and transportation centers in the Metro Detroit area, a region of 5.2 million people, and serves as a major port on the Detroit River connecting the Great Lakes system to the Saint Lawrence Seaway. It was founded on July 24, 1701, by the French explorer, adventurer, and nobleman Antoine de la Mothe, sieur de Cadillac.

In 2010, the city had a population of 713,777 and ranked as the 18th most populous city in the United States. The name Detroit sometimes refers to the Metro Detroit area with a population of 4,296,250 for the six-county Metropolitan Statistical Area, the United States' eleventh-largest, and a population of 5,218,852 for the nine-county Combined Statistical Area as of the 2010 Census. The Detroit–Windsor area, a critical commercial link straddling the Canada–U.S. border, has a total population of about 5,700,000.

Known as the world's traditional automotive center, "Detroit" is a metonym for the American automobile industry and an important source of popular music legacies celebrated by the city's two familiar nicknames, the Motor City and Motown. Other nicknames arose in the 20th century, including City of Champions beginning in the 1930s for its successes in individual and team sport,The D, D-Town, Hockeytown (a trademark owned by the city's NHL club, the Red Wings), Rock City (after the Kiss song "Detroit Rock City"), and The 313 (its telephone area code) Detroit became known as the "great arsenal of democracy" for its support of the U.S. role among the Allied powers during World War II.