Extremadura is the western continuation of the Meseta, but in this region the tableland is more deeply slashed by the trough valleys of the Tagus and Guadiana and their tributaries.
On the north it is separated from Castilla y León by the Sierra de Gata, the Sierra de Béjar and the Sierra de Gredos. It falls away towards Andalusia in the gently sloping Sierra Morena, and is divided by the Sierra de Guadalupe into Extremadura Alta (Upper Extremadura) and Extremadura Baja (Lower Extremadura).The region is dry, and much of it is covered with stony moorland, particularly at the foot of the Sierra de Gata. The growing of corn and pulses is confined to the Cáceres area and Extremadura Baja, frequently exposed to the hazards of inundation by the rivers and devastation by swarms of migratory locusts from the moorland regions. Vines, olives, figs and almonds grow in the valleys, mulberries only in the Plasencia area, where the hillsides are terraced to form orchards. Pig-farming flourishes in the oak forests of Extremadura, and the hams produced there are reckoned to be the best in Spain.
The Tagus traverses the whole length of this nature reserve, in which Mediterranean flora flourishes. The predominant trees are cork-oaks, arbutus, wild olives, holm oaks and, in reafforested areas, eucalyptuses. There are more species of birds of prey to be found here than anywhere else in Spain, including some 46 pairs of black vultures and six pairs of imperial eagles which have found a safe refuge here. Lynxes are occasionally to be seen in the forest.