The Poteau River is a river in the U.S. states of Arkansas and Oklahoma. The only river in Oklahoma that flows north.[1] Poteau is the French word for "post" and it is believed the river was named because French explorers used a post or stake to mark the mouth of the river.[2] The city of Poteau, Oklahoma shares the name of the river. The Poteau River converges with the Arkansas River at Belle Point at Fort Smith, Arkansas, where it serves as a border between the two states for a short distance.