Claim: The Cherven Bryag Municipality is located by the right side of the Iskar River which is a right tributary of the Danube and has a length of 368 km and is the longest river that runs entirely within Bulgaria.
Evidence: The municipality is located by the right side of the Iskar River, close to the inlet of Zlatna Panega River. The Iskar (Bulgarian: Искър, pronounced [ˈiskɐr; Latin: Oescus) is a right tributary of the Danube. With a length of 368 km it is the longest river that runs entirely within Bulgaria.