balgheim lies in a basin on the edge of the baar at the foot of the swabian jura and the dreifaltigkeitsberg (holy trinity mountain). the european watershed, the divide between the rhine and danube watersheds, occurs in the town's territory. the source of the prim, which joins the neckar (a tributary of the rhine) in rottweil, is located only a kilometer away from the source of the faulenbach, an eventual tributary of the danube, in neighboring dürbheim.