Overview
The Arauca River () rises in the Andes Mountains of north-central Colombia and ends at the Orinoco in Venezuela. For part of its run it is the boundary between Colombia and Venezuela. The major city on its banks is Arauca, Colombia and El Amparo, Venezuela.
Course
The Arauca is typical of the rivers that flow east across the Llanos Orientales starting as a swift mountain stream and becoming wider and slower as it crosses the plains.
It starts high in the Andes, in the Páramo del Almorzadero at over above sea level. Initially, it is called the Chitagá, and it receives inflows from the Carabo and the Cacota, and then twists its course towards the east joining with the Culaga and the Bochaga. Its name then changes to the Margua. The Negro, the Colorado, and the San Lorenzo then flow into it.
From the right bank come the Cubugón and the Cobar from the Sierra Nevada de Chita. The Tunebo Indians call this stretch the Sarare. Now flowing across a flat zone, it divides to form the Charo Island. Serving as the demarcation line between Colombia and Venezuela for of border, on the right side, the Royata, Bojabá and Banadía flow in, and on the left the Cutufí enters.
From Wikipedia (CC BY-SA 4.0).