The River Rouge is a 127-mile (204 kilometer) river in the Metro Detroit area of southeastern Michigan. It flows into the Detroit River at Zug Island, which is the boundary between the cities of River Rouge and Detroit.

The river's roughly 467-square-mile (1,210 km²) watershed includes all or parts of 48 municipalities, with a total population of more than 1.35 million, and it drains a large portion of central and northwest Wayne County, as well as much of southern Oakland County and a small area in eastern Washtenaw County. Nearly the entire drainage basin is in urban and suburban areas, with areas of intensive residential and industrial development. Still, more than 50 miles (80 km) of the River Rouge flow through public lands, making it one of the most accessible rivers in the state.

Until recently the river was heavily polluted, and in 1969 oil on the surface caught fire. The passage of the Clean Water Act in 1972 made it unlawful to discharge any pollution from a point source into navigable waters, and the EPA's National Pollution Discharge Elimination Program was created to regulate these discharges.

In 1986, a non-profit organization of concerned citizens called Friends of the Rouge was formed and began organizing an annual cleanup called Rouge Rescue, to raise awareness about the need to clean up the Rouge. In 1987, the entire watershed was designated a Great Lakes "area of concern" under the Great Lakes Water Quality Agreement.

In 1992, a massive project called the Rouge River National Wet Weather Demonstration Project was implemented, and further cleanup measures are ongoing. The Alliance of Rouge Communities is an organization of governmental and non-governmental entities created in 2006 to manage the watershed.

The River Rouge totals 127 miles (204 km) in length and is divided into four branches, the main, upper, middle, and lower branches. The upper branch flows into the main branch in western Detroit within the historic Eliza Howell Park, just east of Redford Township, near the intersection of U.S. Route 24 and U.S. Interstate 96. The middle branch enters the main branch in Dearborn Heights just north of the boundary with Dearborn. The lower branch joins less than two miles (3 km) downstream in Dearborn.

The lower 1.5 miles (2.4 km) of the river south of Michigan Avenue were channelized, widened, and dredged to allow freighter access to Ford's River Rouge Plant inland factory facilities. The plant was built between 1915 and 1927. It was the first manufacturing facility for automobiles that included within the plant virtually everything needed to produce the cars: blast furnaces, an open hearth mill, a steel rolling mill, a glass plant, a huge power plant, and an assembly line. During the 1930s, some 100,000 workers were employed here. The plant has been designated as a National Historic Landmark.

The headwaters of the main branch rise in the southwest corner of Rochester Hills and the northeast corner of Bloomfield Township. It flows mostly south through the western part of Troy, and then flows southwest through Birmingham, a noncontiguous portion of Bloomfield Township, Beverly Hills, the southeast corner of Bingham Farms, and Southfield. It then flows mostly south through western Detroit and Dearborn Heights, then turns southeast in Dearborn and continues along the northern edges of Allen Park, Melvindale, River Rouge and the southern edge of Detroit. Other municipalities that are part of the main branch watershed are Auburn Hills, Bloomfield Hills, Farmington, Farmington Hills, Franklin, Lathrup Village, Oak Park, Orchard Lake, Pontiac, Southfield Township, and West Bloomfield Township.