Coordinates 16°55’ to 18°05’ North and 105°37’ to 107°00’ East. It borders Hà Tĩnh Province on the north with the Ngang mountain pass as the natural frontier, Quảng Trị province to the south, Laos to the west, and faces the Dong Sea to the east. The narrowest part from east (seaside) to west (Laotian border) is just 40 km. The provincial topography is characterized by a general slope, higher in the west and lower in the east, with hilly and mountainous areas accounting for 85% of the total area. The Annamite Range is the natural border between Quảng Bình province and Laos with peaks ranging from 1,000 to 1,500 m, the summit of which is peak Phi Co Pi with the height of 2,017 m. In the east of the province are lower hills and then several narrow plains and river deltas. The seaside sand dunes belt is a natural dam that protects the land from the ocean tides.