The Cestos River, also known as Nuon or Nipoué river,^[3] is a Liberian river that rises in the Nimba Range of Guinea and flows south along the Côte d'Ivoire border, then southwest through tracks of Liberian rain forest to empty into a bay on the Atlantic Ocean where the city River Cess is located. The pygmy hippopotamus (Choeropsis liberiensis) is known to inhabit lands along stretches of the river.^[4] It forms the northern third of the international boundary between Liberia and Côte d'Ivoire.

During the First Liberian Civil War, the portion of the river near the city of Cestos was a leading food and mineral extraction region for the National Patriotic Front of Liberia.^[5]