Situated west of the Davao-Agusan Trough is a complex series of mountain ranges called the Central Mindanao Highlands (also known as the Central Cordillera). From these mountains form the headwaters of several rivers which include the Rio Grande de Mindanao, Pulangi, Maridagao and Tagoloan rivers. Several tall mountains, such as Mount Apo, the country's highest are found within the range.