The Caia () is a river in the

Iberian Peninsula The Iberian Peninsula (), ** * Aragonese and Occitan: ''Peninsula Iberica'' ** ** * french: Péninsule Ibérique * mwl, Península Eibérica * eu, Iberiar penintsula also known as Iberia, is a peninsula in southwestern Europe, defi ...

, a tributary to the

Guadiana The Guadiana River (, also , , ), or Odiana, is an international river defining a long stretch of the Portugal-Spain border, separating Extremadura and Andalusia (Spain) from Alentejo and Algarve (Portugal). The river's basin extends from the ...

. It is one of the main water courses in the

Portalegre District Portalegre District ( pt, Distrito de Portalegre ) is located in the east of Portugal. The district capital is the city of Portalegre. As of 2021, it is the least populous district of Portugal. Municipalities The district is composed of 15 mu ...

Portugal Portugal, officially the Portuguese Republic, In recognized minority languages of Portugal: :* mwl, República Pertuesa is a country located on the Iberian Peninsula, in Southwestern Europe, and whose territory also includes the Macaronesian ...

. Portugal does not recognise the border between the Caia and Ribeira de Cuncos River deltas, since the beginning of the 1801 occupation of

Olivenza Olivenza () or Olivença () is a town in southwestern Spain, near the Portuguese border, on a historically disputed section of the Portugal–Spain border. Its territory is administered by Spain as a municipality belonging to the province of B ...

by Spain. This territory, though under ''de facto'' Spanish occupation, remains a ''de jure'' part of Portugal, consequently no border is henceforth recognised in this area.

Course

It has its sources in the

Serra de São Mamede Serra de São Mamede ( en, Saint Mammes Range) is a mountain range in Portalegre District, Portugal. This range is named after Saint Mammes. Together with the Serra de Arraiolos, the Serra de São Mamede is one of the few places in the Alentejo ...

and for the lower of its course it forms the international Portugal-Spain border. Finally it joins the Guadiana River southwest of the city of

Badajoz Badajoz (; formerly written ''Badajos'' in English) is the capital of the Province of Badajoz in the autonomous community of Extremadura, Spain. It is situated close to the Portuguese border, on the left bank of the river Guadiana. The populatio ...

Tributaries

Arronches Arronches () is a municipality in Portugal. The population in 2011 was 3,165, in an area of 314.65 km2. The municipality is located by the Serra de São Mamede in Portalegre District. The present Mayor is Fermelinda Carvalho ( PSD) and the ...

, also known as ''Alegrete'' * Algalé

Dams

* Caia Dam, with the largest reservoir of Portalegre District

References

External links

Caia Dam - WikiMapia
Rivers of Portugal Rivers of Spain Rivers of Extremadura International rivers of Europe Portugal–Spain border Tributaries of the Guadiana River {{Portugal-river-stub