The Tagus is the longest river in Spain in the Iberian Peninsula, drains an area. The source of the Tagus is the Fuente in the Frías de García. Valdeverdeja is the upper end of the long upper reservoir, the Embalse de Valdecañas. The estuary is protected by the Tagus Estuary Natural Reserve. Former Ribatejo Province and The Portuguese Alentejo region take names from the river.
Portuguese language is the sole official language and a western Romance language, part of the Ibero-Romance group