Rio Cacheu, a significant river in Guinea-Bissau, flows for approximately 257 kilometers, with the Canjambari River as its main tributary. Once a vital commercial route, the river is still navigable by large ships for nearly 100 kilometers inland.

The Cacheu River Mangroves Natural Park, established in 2000, is a Ramsar site since 2015, protecting the largest mangrove forest in West Africa. This ecological haven safeguards fishing resources and shelters diverse flora and fauna, including a haven for migratory birds.