諒山省
The Bắc Giang () is a left tributary of the Kỳ Cùng River. It is 114 km long with a catchment area of 2670 km2 and flows through Lạng Sơn Province and Bắc Kạn Province in northeastern Vietnam. The river originates in Bắc Sơn District in Lạng Sơn Provinceand flows in a northwesterly direction.