Dão is a Portuguese wine region situated in the Região Demarcada do Dão with the Dão-Lafões sub region of the Centro, Portugal. It is one of the oldest established wine regions in Portugal. Dão wine is produced in a mountainous region with a temperate climate, in the area of the Rio Mondego and Dão rivers in the north central region of Portugal. The region became a Denominação de Origem Controlada (DOC) appellation in 1990. The Dão region is the origin of the Touriga Nacional vine that is the principal component of port wine.