Erro (river)

The Erro (in Piedmontese Er) is a 46 km torrent of north-west Italy, a right tributary of the Bormida.

Geography
The river rises in the Ligurian Province of Savona at an elevation 1267 m on Monte Ermetta, to the west of Monte Beigua. Having passed through the territory of Sassello, the river enters the Piedmontese Province of Alessandria at Ponte Erro (Malvicino). Its course takes it past Cartosio, Rivere, Castelletto d'Erro, Arzello, and Melazzo before joining the Bormida at Terzo, a little upstream from Acqui Terme at an elevation of 222 m.