historical provincia, northwesternmost Portugal. It was originally called Entre Douro e Minho, the region between the Minho and Douro rivers. The area was occupied by both the Celts and the Romans, the former having left numerous ruins called castra, or hill forts. There is a narrow coastal plain stretching for about 30 miles (50 km) from north to south and extending between 2 and 10 miles (3 and 16 km) inland to the Santa Luzia Mountains. The rest of the region consists of undulating plateaus traversed by deep valleys of the Minho, Lima, Cavado, and Ave rivers.