The Bia is a river that is situated primarily in Ghana and flows through Ghana and Ivory Coast, emptying into Aby Lagoon on the Ghanaian/Ivory Coast border. A hydroelectric dam was built across the Bia at Ayamé in 1959, causing the formation of Lake Ayame.

The Bia River is one of the transboundary river in west Africa. The River originate in the forested highlands of Ghana at an elevation of 306 meters near the town of Wamfie in the Brong-Region

The Bia River plays a very crucial role in Africa's ecosystem and economy, serving as an important drainage for the Bia Conservation zone in Western Ghana like Sefwi, Aowin and Suaman.