The site was built between 2900 and 2600 BC, though there were possibly earlier buildings before 3000 BC. A tomb was later built into the site. The 13 primary stones form a circle about 13 m in diameter, with a long approach avenue of stones to the north, and shorter stone rows to the east, south, and west. The overall layout of the monument recalls a distorted Celtic cross. The individual stones vary from around 1 m to 5 m in height, with an average of 4 m, and are of the local Lewisian gneiss.