The Uvac (Serbian Cyrillic: 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 115 km, it 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. Also, while meandering through Serbia, Uvac loosely makes the northern border of the Raška region, too.