The Beacon Mound Site in Achasan (Seoul City Monument No. 15, designated in November 1993) used to belong to one of the five beacon fire networks spanning the country during the Joseon period. The mound was part of the following network: Gyeongheung, Hamgyeong – Gangwondo – Ingeup-hyeon Pocheon – Achasan – Namsan, Seoul. The current site is a replica built in November 1994.

The Achasan Beacon Mound is also known as the Bonghwasan Beacon Mound. The summit of Bonghwasan Mountain (160.1m) is the highest point in the neighborhood. The lighting of one hole signified “situation normal,” two holes meant “enemy troops sighted,” three holes warned of “enemy troops approaching,” four holes meant “enemy troops crossing the border,” and five holes heralded “the start of a battle.”

The beacon fire system was established in the early Joseon period, but the government became skeptical about its usefulness around the outbreak of the war with Japan in the late 16th century. It was finally abolished in 1894 (the 31st year of King Gojong’s reign).