Chojijin Fortress was built in 1656 for the purpose of national defense against seashore attacks from foreign enemies. Chojijin Fortress also encompasses the fortifications of Jangjapyeongdon and Seomamdon, which were constructed in 1679. Chojijin was the scene of many hard-fought battles during Byeonginyangyo (the French invasion in 1866), Sinmiyangyo (the American invasion in 1871), and the confrontation with the Japanese warship Unyomaru in 1875. On April 23, 1871, the American navy under the command of Rear Admiral John Rodgers landed on Ganghwado Island, and an American force of 450 soldiers attacked Chojijin Fort, Deokjin Camp, and Gwangseongjin Camp one after another. On August 21, 1875, the artillery of Chojijin engaged a fierce firefight with the Japanese warship Wunyoho. Chojijin Fortress was restored in 1973, and bullet marks still remain on the old pine trees and the fortress walls. The canons used by the military of the Joseon Dynasty are displayed in Chojijin.