Bayou Manchac is an 18-mile-long (29 km) bayou in southeast Louisiana, USA. This bayou was once a very important waterway linking the Mississippi River (west end) to the Amite River (east end). East Baton Rouge Parish lies on its northern side, while its southern side is divided between Ascension Parish (to the east) and Iberville Parish (to the west). The large unincorporated community of Prairieville and the city of St. Gabriel both lie on its southern side.
The bayou was at one time called the d'Iberville River, named for the first Western explorer to have floated it. Iberville had already made his way up the Mississippi and discovered what is now the site of Baton Rouge and wished to find a quick way back to the Gulf of Mexico, where his ships sat at Ship Island. The chief of the Bayogoula tribe, who had accompanied him to the future site of Baton Rouge, on March 26, 1699 showed him the bayou which the Bayogoula used to travel between the present-day Mississippi Gulf Coast and their village. Though it once formed an international boundary, attempts to navigate the bayou as a shortcut between the Mississippi and Amite rivers, or to make it navigable, were generally unsuccessful.
Industrial use and today
Soon Bayou Manchac became one of the most important waterways of southeastern Louisiana. It served the vital role of linking Baton Rouge to Lake Pontchartrain via the Amite River and Lake Maurepas. Through time, as ships became larger and faster, Bayou Manchac was too small to support modern traffic. In the 20th century, when the levees were built, Bayou Manchac was cut off from the river, and later the upper sections dried out or were cut off by roads. Now the bayou is only useful for drainage and recreation, but the area is still regarded by those who live in the vicinity as one of Louisiana's most beautiful examples of nature.
- U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. The National Map Archived 2012-04-05 at WebCite, accessed June 20, 2011