The Sechín River is a seasonal river about 55 km long in the Ancash department of Peru that remains dry for long seasons, increasing its volume at times of rain in the mountains at its source. It is of irregular regime, due to this is known as Loco River. It rises at an altitude of 4,385 m (14,386 ft) in the Cordillera Negra and it ends by flowing into the Casma River about 10 km inland from the Pacific Ocean. The Casma-Sechin basin runs down the western slopes of the Andes mountain range - one of the world’s driest deserts. The city of Casma, population 30,000, is located near the junction of the two rivers. The Pan-American Highway crosses the Sechin River at Casma.