Lạng Sơn () is a city in far Northern Vietnam, which is the capital of Lạng Sơn Province. It is accessible by road and rail from Hanoi, the Vietnamese capital, and it is the northernmost point on National Route 1.
Wikipedia https://en.wikipedia.org/wiki/Lạng_Sơn
Coordinates 21°51'10.353" N 106°45'35.085" E