Ban Gioc – Detian Falls (in Vietnamese: thác Bản Giốc, in Chinese: Détiān pùbù, Bǎnyuē pùbù 板約瀑布, 德天瀑布) are two waterfalls on the Quây Sơn River, in Chinese Guichun River, straddling the Sino-Vietnamese border, located in the Karst hills of Daxin County, Guangxi (Chinese side), and in Trùng Khánh District, Cao Bằng province on the Vietnamese side, 272 km (169 mi) north of Hanoi.