Old River
General data
- Name: Old River
- Water system: Atchafalaya River
- Water type: River
- Progression: Black River (Red River tributary) -> Red River of the South -> Atchafalaya River -> Gulf of Mexico -> Atlantic Ocean -> Planet Earth
- Climates: Subtropical, Temperate, Subtropical
- Continents: North America, North America
- Countries: United States of America, United States of America
Old River (Catahoula area Old River) is the natural outlet channel on the southwestern side of Catahoula Lake. Historically, it served as one of the main natural outflows for Catahoula Lake, carried water from the lake toward the Black River system.