Kwanbuk

Kwanbuk is a region in North Hamgyong Province of North Korea. The region may once have been occupied by the Okjeo people. It was later controlled by Goguryeo and then Balhae, and subsequently contested by Goryeo and the Jin dynasty.
Its literal meaning is "North of the Ridge", the ridge (Korean, "kwan") in question being Mach'ŏnnyŏng (Chosŏn'gŭl: 마천령, Hancha: 摩天嶺). 
The term Kwanbuk is no longer widely used.