Lào Cai is a mountainous region. In the northwest of the province is Phan Xi Păng (also called Fansipan; elevation , snow covered during winter season), Vietnam's highest mountain. It is located in the Hoàng Liên Sơn and the Hoàng Liên National Park. The Sa Pa Mountains form the western part of the province. While the province is drained by over 100 rivers, the main river that bisects the province is the Red River, (), the most significant river of northern Vietnam, which flows out of China towards the capital Hanoi. It flows through the province over a length of . Other rivers of significance are the Chay and Nam Ti Rivers. Much of the province is heavily forested.