The Isce Îen River starts in the mountains of The White March and passes near Cold Morn. It separates the erldom of Cold Water from Eir Glanfath. As it travels southward towards the ocean, it also separates the erldoms of The Grasp and Baelreach. The river passes by Caed Nua, which is located near the bank.
In 2823 AI, due a flash flood, the river washed out the Madhmr Bridge, which was the direct route from Defiance Bay to Gilded Vale. A temporary ferry service was established to carry travelers over the river.