In the local language, Pha Din means Heaven-Earth, and according to local legend, it was the frontier between Heaven and Earth.

Pha Din is some 1,000m above sea-level. Climbing and descending the slopes with their many bends and deep gorges is a really interesting trip amid such a magnificent scenery.

Pha Din pass that is about 32 km long. Pha Din means the earth and the sky in the language of Thai ethnic group.

According to a legend of the local, it is the place where the sky meets the earth. Long time ago, there existed a deputation on the border between Lai Chau and Son La provinces. It was solved by a horse-racing. Two horses started from each side of the pass and the border was determined at the point where they met each other. The horse of Lai Chau province ran faster than the one of Son La province so the pass belonging to Lai Chau is longer than that of Son La.

At the height of above 1,000m, the pass is full of twists and turns, one side is a upright cliff and the other is a deep gulf. Therefore, visitors will have a chance to enjoy the natural landscape in the North-west area.