O Quy Ho pass or Hoang Lien Son pass is on the national highway 4D in the area adjacent to two provinces Lao Cai and Lai Chau, Vietnam. The pass crosses Hoang Lien Son mountain, the top of the pass is near the border between the two provinces. The official name of the pass in the waterway is Tram Ton Pass. It is also known locally as Heaven Gate, or also called Cloud Pass because it is covered with clouds all year round. However, tourists often know the pass with the name O Quy Ho Pass.
With a total length of about 50,000 m, this is the longest pass in Indochina with a long, rugged and majestic mountain pass in the most mountainous area of Northern Vietnam. The top of the pass is about 2,000 m above sea level.
The pass is related to a legend about Love waterfall, where a fairy and a lumberman named O Quy Ho met and fell in love with each other. Unable to be married, the fairy turned into a bird and flew over the mountain, calling his name O Quy Ho. Since then, over time the cry of “o quy ho” of the bird has been named for the wild pass at an altitude of nearly 2,000 m.
O Quy Ho Pass is one of the most attractive destinations in Northwest Vietnam. Endowed with nature, its beauty offers travelers a majestic and marvelous natural landscape.
From O Quy Ho pass, the entire majestic scenery of Mount Fansipan, the highest mountain in Indochina, comes into sight. At the top of the pass, what can be seen is the beautiful valleys of Lai Chau below.
The climate on both sides of O Quy Ho pass, in Lai Chau and Lao Cai provinces, is very different throughout the year. When it’s warm and sunny in Lai Chau, it’s cold and cloudy in Lao Cai, and vice versa. During the cold weather, the peak of O Quy Ho pass can be covered with snow and ice.
As one of the most difficult and winding roads in Vietnam's northwest mountains, O Quy Ho Pass inspires a lot of adventurous travelers.