Bayou Manchac
General data
- Name: Bayou Manchac
- Water system: Gulf of Mexico
- Water type: River
- Progression: Amite River -> Lake Maurepas -> Pass Manchac -> Lake Pontchartrain -> Chef Menteur Pass -> Lake Borgne -> Gulf of Mexico -> Atlantic Ocean -> Planet Earth
- Climates: Subtropical
- Continents: North America
- Countries: United States of America
Bayou Manchac is a waterway in southeastern Louisiana, running roughly east-west between the parishes of East Baton Rouge (north side) and Ascension / Iberville (south side). It is about 29 km long. The watershed drained by Bayou Manchac covers about 152 square miles. The bayou empties into the Amite River — its flow runs eastward from its (historical) source near the Mississippi, passes through various terrain (natural levees, backswamps, Pleistocene hills), then joins the Amite River.