The river Luna was a clear Barovian central river stemming from Lake Zarovich south of Mount Baratok. From the lake, its water flowed lazily under the stone bridge of the Luna River Crossroads before it began to widen and swell past the marshy ruins of Berez; the river had been magically widened to swell to multiple hundreds of feet across to enact the Flooding Of Berez at the behest of Strahd von Zarovich.
Rivers draining from Mount Ghakis met Luna Lake in a confluence before Tsolenka Pass, where the waters becoming a tributary of Luna Lake.