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 does not recognise the border between Caia and Ribeira de Cuncos River deltas, since the beginning of the 1801 occupation of Olivenza 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. It runs into the Guadiana river.