The Rio Mondego (Portuguese pronunciation: [ˈʁi.u mõˈdeɣu]) or Mondego River is the longest river entirely within Portuguese territory.[1] It has its source in Serra da Estrela, the highest mountain range in mainland Portugal (i.e. excluding the Portuguese islands). It runs 234 kilometres (145 mi) from the Gouveia municipality, at 1,425 metres (4,675 ft) above sea level in Serra da Estrela, to its mouth in the Atlantic Ocean next to the city of Figueira da Foz. Its etymology is believed to be a pre-Roman, Hispano-Celtic voice Munda or Monda (*mundikos/*-moundikos < lat. *mundicus, -a),[2][3][4] Latinised into Mundicus < Mondæcus[5] until evolving into the present name.