The walled town was built with soil to protect against the Japanese invasion in Joseon, considering the past frequent aggressions in the end of Goryeo.
It was built in 1397, the 6th year of the reign of King Taejo in Joseon, for the first time.
Looking at the Sejongsillok (Annals of King Sejong) after that time, the fortress has been rebuilt and expanded over many years since 1423.
Most types of fortress are rectangular and are about 1,410m long.
There are gates connected with a wide road within the fortress in the east-south and west-south, and part of the fortress protrudes to protect effectively against the attack of the enemy.
Since the village within the fortress has traditional aspects preserved, one can have a glimpse of the lifestyle and culture at that time.
Naganeupseong is one of the remaining well-maintained styles of fortresses that realistically show the style in the early Joseon period.