Ganghwa dolmens were located at Bugeun-ri, Samgeo-ri, Gocheon-ri, Osang-ri, and Gyosan-ri, Hajeom-myeon, Ganghwa-gun, Incheon. 127 dolmens were distributed at the northern foot of the Mt. Goryeo. It was historically important area as the island of estuary of the Han river.
Total 70 dolmens including 14 dolmens at Bugeun, 9 at Samgeo-ri, 20 at Gocheon-ri, 12 at Osang-ri, 13 at Gyosan-ri, 1 at Daesan-ri and 1 at Bugeun-ri were registered as the world heritage.
Ganghwa dolmens showed very various distribution conditions like the foot of mountain, hill, flat land and ridge. Dolmens at Gyosan-ri and Gocheon-ri were at the ridge and those at Bugeun-ri and Samgeo-ri were at flat land. Table-type dolmens at Bugeun-ri were located at the land of 20~30m formed at the northern foot of the Mt. Goryeo and there was the Geumgok river running into the sea.
Dolmens at Bugeun-ri, known as Ganghwa dolmen (Historic Site No. 137) were dolmens familiar with us because it was included in elementary school textbook. It was located within Ganghwa Dolmen Park at 317, Bugeun-ri, Hajeom-myeon and designated, protected and managed as Historic Site in 1964.
The size of capstones of this dolmen was 6.40m in length, 5.23m in width and 1.12m in thickness and its whole height was 2.45m. 2 big upright stones were under the center of capstones and left and right upright stones remained. Supporting stones are tilted 30° to the east and capstones were vertically positioned on the ground. The rocks of capstones were migmatite gneiss, left upright stones were mica schist, and right upright stones were granitic gneiss.
This dolmen show grand look by big capstones on the ground and has the function of monument and altar to symbolize the group building it.
12 dolmens excavated at Osang-ri, Ganghwa were repaired and restored. Dolmen group was located at small mountain of 76m above sea level at the end foot of the Mt. Goryeo and the dolmen which was the largest among these dolmens was 'Naegajiseokmyo', designated as Local Monument No. 46. Dolmens have capstones of upright stones of 50 cm in height.
As a result of excavation by Sunmun University in 2000, various stone tools and burnished red potteries including stone dagger, stone arrowhead, stone ax, etc. were excavated.
Dolmen group at Gocheon-ri was at the west top of the ridge from the top of Mt. Goryeo to Jeokseoksa Nakjobong, 300~350m above sea level.
20 dolmens at 3 groups were distributed and most of them were table-type dolmens with low height. Most of the capstones were buried with fallen leaves and soil.