Thac Bo Cave

Thac Bo Cave is a natural limestone cave located on Hoa Binh Lake in Cao Phong District, Phu Tho Province (formerly Hoa Binh Province). Situated on the Da River reservoir, it is accessible only by boat. The cave is known for its extensive stalactites and stalagmites, large chambers, and Buddhist shrine inside. It forms a combined visitor complex with nearby Thac Bo Temple and is a prominent stop on Hoa Binh Lake boat tours.

Visitors reach Thac Bo Cave by boat across Hoa Binh Lake from Thung Nai or Binh Thanh pier, enjoying lake and karst scenery. The cave entrance is reached via stone steps from the water's edge. Inside, visitors can explore large chambers filled with stalactites and stalagmites in various shapes, illuminated for viewing, with a small Buddhist altar area. The interior is cool, damp and can be slippery. The visit typically includes photography, sightseeing inside the cave, and views of the lake and surrounding limestone hills.

Thac Bo Cave is a natural karst cave formed over thousands of years in the limestone mountains flooded by the Hoa Binh Hydropower Reservoir in the 1980s. It is historically linked to Thac Bo Temple, which honors the spirits believed to protect the Da River area, and has long been a place of local pilgrimage.

The cave holds religious significance as a spiritual site with Buddhist altars and statues inside, where visitors pray for peace and good fortune. It is closely associated with the worship of Ba Chua Thac Bo (Lady of Thac Bo), part of the Mother Goddess worship tradition, and is visited together with Thac Bo Temple during festivals, especially in spring.