Đồng Đăng is a town of Cao Lộc District, Lạng Sơn Province, Vietnam. It is best known as a border town on the Vietnamese side of the main road and rail crossing to China. It is on National Route 1A. Đồng Đăng Railway Station and the town are several kilometres short of the Friendship Pass border crossing. It is one of three main border crossings with China, the others being Móng Cái-Dongxing, Guangxi to the East on the coast, and Lào Cai-Hekou, Yunnan, inland 150 km northwest. A fourth crossing is the Trà Lĩnh District-Longbang, Guangxi crossing.