Korean fortresses are fortifications constructed by Koreans since the Three Kingdoms of Korea period. Koreans developed a unique and distinct fortress tradition. Korea, beginning with Goguryeo, has been called "a country of fortresses"; almost 2,400 mountain fortress sites have been found in Korea.

Goguryeo also later known as Goryeo, was a Korean kingdom which was located in the northern and central parts of the Korean Peninsula and the southern and central parts of modern day Northeast China. At its peak of power, Goguryeo conquered most of the Korean Peninsula and large parts of Manchuria, along with parts of eastern Mongolia, Inner Mongolia, and modern-day Russia.