Detroit–Windsor in the context of "Windsor, Ontario"

The Detroit River is an international river in North America. The river, which forms part of the border between the U.S. state of Michigan and the Canadian province of Ontario, flows west and south for 24 nautical miles (44 km; 28 mi) from Lake St. Clair to Lake Erie as a strait in the Great Lakes system. The river divides the metropolitan areas of Detroit, Michigan, and Windsor, Ontario—an area collectively referred to as Detroit–Windsor. The Ambassador Bridge, the Detroit–Windsor Tunnel, and the Michigan Central Railway Tunnel connect the cities.

The river's English name comes from the French Rivière du Détroit (translated as "River of the Strait"). The Detroit River has served an important role in the history of Detroit and Windsor, and is one of the world's busiest waterways. It is an important transportation route connecting Lake Michigan, Lake Huron, and Lake Superior to Lake Erie and eventually to Lake Ontario, the St. Lawrence Seaway and the Erie Canal. When Detroit underwent rapid industrialization at the turn of the 20th century, the Detroit River became notoriously polluted and toxic. Since the late 20th century, however, a vast restoration effort has been undertaken because of the river's ecological importance.

The Great Lakes megalopolis consists of a bi-national group of metropolitan areas in North America largely in the Great Lakes region. It extends from the Midwestern United States, and part of the Southern United States in the south and west to western Pennsylvania and Western New York in the Northeastern United States and northward through Southern Ontario into southwestern Quebec in Canada. It is the most populated and largest megalopolis in North America.

At its most inclusive, in the United States the region cuts a wide swath from the Twin Cities of Minneapolis–Saint Paul in Minnesota in the west, south to St. Louis and Louisville, Kentucky, and east to Rochester, New York; in Canada, it continues northeasterly to Quebec City. This broader region had an estimated population of 59,144,461 as of 2011 and is projected to reach a population of about 65 million by 2025. Within this broad region, there is a core area of more continual urban development that includes Chicago, Milwaukee, Grand Rapids, South Bend, Fort Wayne, Indianapolis, Detroit–Windsor, Cincinnati, Columbus, Cleveland, Toledo, Pittsburgh, Buffalo, Rochester, Toronto, Ottawa, Montreal, and the metropolitan areas between these.

The Ambassador Bridge is an international suspension bridge across the Detroit River that connects Detroit, Michigan, United States, with Windsor, Ontario, Canada. Opened in 1929, the toll bridge is the busiest international border crossing in North America in terms of trade volume, carrying more than 25% of all merchandise trade between the United States and Canada by value. A 2004 Border Transportation Partnership study showed that 150,000 jobs in the Detroit–Windsor region and US$13 billion in annual production depend on the Detroit–Windsor international border crossing.

The bridge is one of the few privately owned US–Canada crossings; it was owned by Grosse Pointe billionaire Manuel Moroun, until his death in July 2020, through the Detroit International Bridge Company in the United States and the Canadian Transit Company in Canada. In 1979, when the previous owners put it on the New York Stock Exchange and shares were traded, Moroun was able to buy shares, eventually acquiring the bridge. The bridge carries 60 to 70 percent of commercial truck traffic in the region. Moroun also owned the Ammex Detroit duty-free stores at both the bridge and the tunnel.