The Uvac (Bosnian, Serbian: Uvac, Увац) is an international trans-boundary river, rising under Golija mountain and Pešter plateau, then flowing through southwestern Serbia and cross into eastern Bosnia and Herzegovina where, after 119 km, finally meets the Lim river from the right, however, before it empties into the Lim, for a 10 kilometers Uvac forms the border between two countries.