The Amsa Neolithic Site, located on 37°33′ latitude and 127°10′ longitude, was formed on ancient river banks. It is 60km apart from the Odusan at the mouth of the Han river near the Yellow Sea and 15km downstream from merging point of two major tributaries in Yangsuri.
Han river was merged by several tributaries in up stream from the Amsadong site and abraded in much wider and flat plaines from the Amsadong site.

The Amsadong site is situated on river terrace left by the major channel stream which settled down at current position near the other side of the Han river. Settlements of Neolithic and Three Kingdoms Period were found in silty sand layers of mixed origins on the top part of the fluvial deposits of the terrace. Regression of stream channels from this area was probably caused by minor climate changes during the eraly Hokocene, however settling down with deep channel bottom at the other side of rive would be also one of major factors leaving ancient flood plain in this area without further fluvial actions any more which would be very suitable for fishing village in early Neolithic period.