Rio Dão is a Portuguese

Portugal

Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...

 river that originates in the plateau regions of Trancoso-Aguiar da Beira in the Eirado parish, Aguiar da Beira Municipality, Guarda District, and varies between 714 meters and 757 meters in elevation.

It flows in a general NE-SW direction, passing through Barragem de Fagilde and crosses or demarcates the limits of the councels of Aguiar da Beira, Penalva do Castelo, Mangualde, Viseu, Carregal do Sal, Nelas, Tondela, and Santa Comba Dão. It empties into the Mondego river, in the limits of the councils of Santa Comba Dão, Mortágua, and Penacova, after covering about 100 kilometres.

Its main tributaries are the Carapito River, Ribeira de Coja, Sátão River and the Criz River. Its granite-sloped valley is situated in the "Região Demarcada do Dão", where the Vinho do Dão

Vinho do Dão

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...

table wines are produced.