Quảng Ninh has a common international border with the People's Republic of China. Inland, north of province (Bình Liêu, Hải Hà districts) and Móng Cái borders Dongxing City and Fangcheng County in Guangxi, PRC with the borderline of 170 km. To the east, it adjuncts to Bắc Bộ Gulf. The province also borders Lạng Sơn, Bắc Giang and Hải Dương provinces to the west, and the city of Hải Phòng to the south. The coastal line is 250 km. The total area of Quảng Ninh is 8,239.243 km2, of which 5,938 km2 is mainland. The area of islands, bays and sea is a tremendous 2,448.853 km2. The total area of the islands is 619.913 km2.