Chamseongdan
Chamseongdan is an ancient altar located at the summit of Manisan in Hwang-ri, Hwado-myeon, Ganghwa County, Incheon, South Korea. It is traditionally believed to have been built by Dangun, the legendary founder of Gojoseon, during ancient times. On July 11, 1964, it was designated as Historic Site No. 136 of South Korea.
Description
The structure of Chamseongdan consists of a circular lower altar constructed with natural stones and a square upper altar placed above it. The lower section measures approximately 4.5 meters in diameter, and the upper platform is 1.98 meters square. The design is based on a traditional concept that associates circular forms with the sky and square forms with the earth.History
Chamseongdan is traditionally associated with Dangun, the legendary founder of Gojoseon, and is believed to have been the site of ritual offerings to heaven. Historical sources such as the Goryeosa describe it as an altar where Dangun conducted such rites, and the Sejong Sillok Jiriji notes that it was constructed using stone.The site has undergone several documented restorations, including repairs in 1270, reconstruction in 1639, and renovation in 1700. Chamseongdan is also mentioned alongside Samnangseong in later records, with both sites being linked to Dangun-related traditions. The area surrounding Ganghwa Island, including the Han River basin, has been identified in some historical interpretations as part of the southern boundary of Gojoseon.