The Biá River (Portuguese: Rio Biá) is a river of Amazonas state in north-western Brazil.

It is a tributary of the Jutaí River.

The 2,450,380 hectares (6,055,000 acres) Cujubim Sustainable Development Reserve, established in 2003, lies on either side of the river in the municipality of Jutaí.

[2] It is the largest conservation unit in Amazonas and the largest sustainable development reserve in the world.

This article related to a river in the Brazilian state of Amazonas is a stub.