The Douro (UK: /ˈdʊər, ˈdʊər/, US: /ˈdɔːr, ˈdɔːr, ˈdru/,[1][2][3][4] Portuguese: [ˈdo(w)ɾu]; Spanish: Duero [ˈdweɾo]; Latin: Durius) is the highest-flow river of the Iberian Peninsula. It rises near Duruelo de la Sierra in Soria Province, central Spain, meanders south briefly then flows generally west through the north-west part of central Spain and into northern Portugal, to its mouth at Porto, the second largest city of Portugal. At its mouth it meets the Atlantic Ocean.

Duero  (Spanish)
Douro  (Portuguese)
The river flowing through the Portuguese wine region, designated as a World Heritage Site.
CountrySpain, Portugal
Physical characteristics
SourcePicos de Urbión
  locationSistema Ibérico, Duruelo de la Sierra, Soria, Castile and León, Spain
  coordinates42°0′38″N 2°52′49″W
  elevation2,157 m (7,077 ft)
MouthFoz do Douro
Atlantic Ocean, Porto, Greater Porto, Norte, Portugal
41°8′36″N 8°40′10″W
0 m (0 ft)
Length897 km (557 mi)
Basin size98,400 km2 (38,000 sq mi)
  average700 m3/s (25,000 cu ft/s)
  maximum17,000 m3/s (600,000 cu ft/s)
  average442 m3/s (15,600 cu ft/s)
Basin features
  leftTera [es], Rituerto [es], Riaza [es], Duratón, Cega, Adaja, Tormes, Águeda, Côa, Torto [pt], Távora, Varosa [pt], Bestança [pt], Paiva [pt], Arda, Inha [pt]
  rightPisuerga, Valderaduey [es], Esla, Sabor [pt], Tua, Corgo, Tâmega, Sousa

The river is notable for the scenic Douro railway line, tourism more generally and relatedly the creation and production of a mildly fortified wine: port, grapes, conventional wines and other agricultural produce. A small tributary of the river has the Côa Valley Paleolithic Art site which is considered important to the archaeological pre-historic patrimony, designated a UNESCO World Heritage Site.