Fansipan or Fan Si Pan (Phan Xi Păng in Vietnamese pronunciation) is a mountain in Vietnam, the highest in Indochina, at 3 143 m. It is located in the Lào Cai province in Northwest Vietnam, 9 km southwest of Sa Pa Township in the Hoang Lien Son Mountain Range. Fansipan is dubbed "the Roof of Indochina"; it is to be approved as one of the very few ecotourist spots of Vietnam, with about 2,024 floral varieties and 327 faunal species.  

The topography of Fansipan is varied. Muong Hoa Valley, at the lowest altitude (950 to 1 000m), is created by a narrow strip of land at the base on the east side of the mountain. It can be climbed in a steep and fairly strenuous hike.

Fansipan tourism tours are ususually arranged hikes to the summit taking from one to three days. Most will recommend taking the two- or three-day options guided