Compiling research material and that of academic investigation is fragmentary and has been conducted by each small unit (city, gun, or local government). Therefore, Naju National Research Institute of Cultural Heritage felt the necessity of systematic and comprehensive research investigation and collection of the material by the field and kind in each wide regional zone, and thus has been conducting the investigation and research in the Youngsan river basin as the first stage. The dolmens found in the upper region of Youngsan river are estimated at 2,644 in the total of 459 places— which are 579 more in 131 places compared to the information that the cultural heritage GIS– Heritage Geographic Information System, hereinafter GIS– established in 2010. In the investigation, there appeared to have errors in terms of the location, scope, name, other types and duplication, and among the errors, locational one takes the biggest part. Though there are 279 dolmens in 106 places in Jangseong-gun. Among the errors in GIS, locational errors are 36 (47.7%) of them, taking the biggest part in the 76 places of the dolmens. There are 280 dolmens in the total of 94 places in Damyang-gun. Locational errors in GIS are 42 cases (59.2%), taking the biggest part among the dolmen in 70 places. There are 359 dolmens in the total of 78 sites in Gwangju. The error rate of GIS in the region is the lowest compared with the other three regions, taking 32.6%, and among the errors, scope errors are 7(15.2%) being the biggest in the region. Hwasun-gun has 1,726 dolmens in the total of 181 sites.. Both locational and scope error in GIS are similar in the region–the locational ones are 25 (24.5%) and that of scope are 29 (28.4%). The age of the dolmens in the upper region of Youngsan river can be estimated using the stone daggers and arrows excavated from the tombs. In the dolmens in Jangseong-gun, there are no excavated remains such as patternless earthware, stone dagger or stone arrow, but the age can be thought to have been made in the late Bronze Age, considering the excavated materials in Damyanggun, Gwangju or Hwasun-gun. Both hilted stone dagger and tanged dagger were found in the tombs, and that form of excavation is largely thought of that in the late Bronze Age. Since all the stone arrows found are having one tail except one, the central age of the tombs can be thought in the late Bronze Age. The lowest limit of the age of the dolmen is considered between 4 B.C. and 2 B.C. from the clay pottery found in the fifth dolmen in A-group and the clay patchstand in the fifth one in B-group in Maewol-dong, Gwangju.