The Arga is a river of Navarre, in Spain, and is a tributary of the AragĂłn River, itself a tributary of the river Ebro. The Arga was known as the river Runa in antiquity. Situated in the north-east of Spain, the river stretches some 145 kilometres (90Â mi) and has a basin of 2,759 square kilometres (1,065Â mi), of which 2,652 square kilometres (1,024Â mi) is in Navarre and the remaining 107 square kilometres (41Â mi) is in the province of Alava. The source of the river is to the north of the village EsterĂbar, near the border with France, and it empties into the AragĂłn River near Funes.
The river is dammed in the Eugui reservoir near EsterĂbar; the dam principally serves the needs of Pamplona's metropolitan area, the largest city on the Arga.