One of the major rivers of the Iberian Peninsula, the Douro flows from its source in north-central Spain through Portugal and runs about 560 miles to its outlet at Porto on the Atlantic Ocean. Its name comes from the ancient Celtic tribal word for water. The river is wild and meandering; only certain parts of it are navigable by small river vessels. The area is beautiful and unspoiled and features a very habitable microclimate where olives, almonds and especially wine grapes are grown. Scenery along the river is picturesque, dotted by terraced hills, small towns and traditional rabelo sailing boats with their casks of port wine.
The area in and around Pinhão is considered to be the center of port wine, with wine-producing quintas (farms) dotting the slopes that line the river.
The Douro is quite narrow in parts and water levels have historically been inconsistent, but there are now five dams on the Portuguese section of the river which have helped to stabilize water levels and also produce some electric power. The dams have allowed the scheduling of river cruise excursions along the Douro River Valley.