Mountainous Bac Son, Bac Son of the bow of northeastern Vietnam. In the district there are 500-1200 m high mountains, such as Ao Pi Khau mountain (1.107m high), Lev Pa mountain (503 m) ... Bac Son district is bounded north by the districts of Binh Gia, Van Quan district on the east, south Huu Lung district, both districts of the province of Lang Son. Particularly west, Bac Son district bordering district of Thai Nguyen Vo Chew. Natural area of Bac Son district is 697.9 km2.