The Ralban flows west from the great swamp Gurutharni. It is fed by swamps along its flow west and the torrential run-off from the Kilth mountains. At its head, is the dense foliage of Kazzatar where jungle canopies can leave large swathes of the river in low-light conditions. This foliage begins to thin as it heads closer to the mountains and into western Ma'Ohari. In the western tracts of Ma'Ohari, the river bends south, cutting through a valley and then jungle lowlands before emptying into Salzârrâk.
The river has long served as route of raiding and pirating by bandits and the yuan-ti of Malshirk'iss and to those serving even darker masters under the demon reign of Varelay.
The largest settlement on the Ralban is Tâchumâz. Near the headwaters of Ralban is the yuan-ti city Phlem.
Ralban is haven to serpents, giant crocodiles, yuan-ti, and other beasts. As early as the Second Epoch, the yuan-ti have been charging tolls for that part of the river that falls in their territory. One of the reasons that started the Serpent Reckoning (1475 - 1478) war was the refusal by the Kingdom of Bloodtusk to pay these time-honored tolls.