The Caia () is a river in the

Iberian Peninsula The Iberian Peninsula ( ), also known as Iberia, is a peninsula in south-western Europe. Mostly separated from the rest of the European landmass by the Pyrenees, it includes the territories of peninsular Spain and Continental Portugal, comprisin ...

, a tributary to the

Guadiana The Guadiana River ( , , , ) 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 la Mancha and the e ...

. It is one of the main water courses in the

Portalegre District Portalegre District ( ) 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. It borders Spain. Municipalities The district is composed of 15 municipalit ...

Portugal Portugal, officially the Portuguese Republic, is a country on the Iberian Peninsula in Southwestern Europe. Featuring Cabo da Roca, the westernmost point in continental Europe, Portugal borders Spain to its north and east, with which it share ...

. Portugal does not recognise the border between the Caia and

Ribeira de Cuncos Ribeira de Cuncos is a Portuguese ravine that marks the southern point of the disputed section of the Portugal-Spain border, (Arroyo de Cuncos in Spanish). Portugal Portugal, officially the Portuguese Republic, is a country on the Iberi ...

River deltas, since the beginning of the 1801 occupation of

Olivenza Olivenza () or Olivença () is a town in southwestern Spain, close to the Portugal–Spain border. It is a municipality belonging to the province of Badajoz, and to the wider autonomous community of Extremadura. The town of Olivença was und ...

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 () 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 region where there might ...

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 is the capital of the Province of Badajoz in the autonomous communities of Spain, autonomous community of Extremadura, Spain. It is situated close to the Portugal, Portuguese Portugal–Spain border, border, on the left bank of the river ...

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