The Bila river is the largest tributary of the Lašva river. The Bila river flows past the settlements of Old and New Bila, with a length of approximately 35 km. Originating from Vlašić mountain, in the area of Prelivode, the mouth of the Bila river joins with the Vrbanja, Ilomska, and Ugar rivers, at about 1,550 meters above sea level. In the pass between the Vlašić (1943 m) and Meokrnje (1,425 m) mountains, the mouth of the river is approximately 2.5 km wide. On the western slopes of Vlašić Mountain, the Bila river flows through the villages of Bukovica and Mehurići. It often floods and has significant hydro potential.