The northeastern flank of the Cordillera Real is known as the Yungas, from the Aymara word meaning "warm valleys." The steep, almost inaccessible slopes and peaks of this mainly semitropical valley area northeast of La Paz offer some of the most spectacular scenery in Bolivia. Rainfall is heavy, and lush vegetation clings to the sides of narrow river valleys. The land is among the most fertile in Bolivia, but poor transportation has hindered its agricultural development. The government attempted to build a railroad through the Yungas in 1917 to connect La Paz with the eastern lowlands. The railroad was abandoned, however, after completion of only 150 kilometers.

The eastern slopes of the Cordillera Central descend gradually in a series of complex north-south ranges and hills. Rivers, draining to the east, have cut long narrow valleys these valleys and the basins between the ranges are favorable areas for crops and settlement. Rich alluvial soils fill the low areas, but erosion has followed the removal of vegetation in some places. The valley floors range from 2,000 to 3,000 meters above sea level, and this lower elevation means milder temperatures than those of the Altiplano. Two of Bolivia's most important cities, Sucre and Cochabamba, are located in basins in this region.

Data as of December 1989