The Sarne's western tributaries begin in the hills south of Vaes Khadokh, while its eastern tributaries have their sources in the western Dothraki sea. The Sarne flows north into the Shivering Sea, with the cities of Saath and Morosh and the ruins of Vaes Graddakh located in the Sarne delta. A Valyrian road connecting Vaes Khadokh to Vaes Khewo crosses the Sarne.
The ancient Kingdom of Sarnor developed around the Sarne and its tributaries. Sarnath, the seat of the High King of the Sarnori, was located along the southwestern branch of the Sarne. However, the grassland kingdom and its cities were ruined by the Dothraki in the Century of Blood following the Doom of Valyria.