Caraballo Mountains are mountains in central Luzon inhabited by a community called Ilongot. These are thickly forested mountains close to the upper end of Cagayan Valley; separating it from the Central Plains of Luzon. Caraballo reaches an elevation of about 5,500 ft or 1,680 m. and joining the Central Cordillera to the north and the Sierra Madre to the east. Drained by the headwaters of the northward flowing Cagayan River, the mountains are heavily forested. Trails and roads did develop through these mountains but they were difficult to cross and many times would be destroyed by rain and mud slides during rainy season. Because these mountains offered no known economic benefits, people were also left isolated from the lowlands. They also serve to discourage travel between central Luzon and Nueva Vizcaya.