The River Agis flowed from the east out of the Marching Mountains and into the Trackless Sea near the city of Memnon. The river was called the Memnon River in most of Tethyr. It served as the border between Calimshan and Tethyr ever since the Eye Tyrant Wars. The river was wide and slow-moving and very suitable for cargo-carrying barges and lumber. However, it did not receive as much traffic as would be expected owing to fears regarding Shoonach, as Port Agis, a section of Shoonach, also lay along the river upstream.