Quảng Bình Province

Quảng Bình Province (Vietnamese: Tỉnh Quảng Bình) is a province of Vietnam. It is located in the North Central Region and is bordered by Hà Tĩnh Province to the north and Quảng Trị Province to the south, and Laos to the west.

Its capital and largest city is Đồng Hới, located in the east of the province near the Gulf of Tonkin coast. The province is known for the Phong Nha National Park, home to Hang Sơn Đoòng, the largest cave in the world. It was the southernmost province of the former Democratic Republic of Vietnam (North Vietnam).

Geography
The province is located at the narrowest point of Vietnam. It has a low coastal plain on the Gulf of Tonkin and rugged inland mountains, most of which are a part of Phong Nha National Park in the Annamite Mountains. The area is littered with caves, including Hang Sơn Đoòng, the largest cave on earth.

In the northwest of the province is the Mụ Giạ Pass, a gap in the Annamite Mountains that serves as a major connection between Vietnam and Laos by road and rail.