Lang Son is a frontier mountainous province in the North-East of Vietnam. It shares border with Cao Bang Province on the south, Bac Giang Province on the north, Guangxi (China) on the east, Quang Ninh Province on the north-east and Bac Kan, Thai Nguyen provinces on the west.
Mountains and hills cover over 80% of the province's total area. The complex network of rivers makes a good condition for agriculture. Main rivers that run through the province are: Ky Cung, Ba Thin, Bac Giang, Bac Khe, Thuong, Hoa, and Trung rivers.
Lang Son has two international border gates including Dong Dang railway border gate and Huu Nghi road border gate, two national border gates such as Chi Ma (in Loc Binh District) and Binh Nghi (in Trang Dinh District)... So Lang Son has an important strategic position in the North-East of Vietnam.
The climate is cool and temperate. Annual average temperature is 21.5ºC. Annual average rainfall is from 1200mm to 1600mm.