Auchenlaich is a remarkable site being the longest burial cairn in Britain.

Stretching some 350m approximately north-north-west to south-south-east it is situated on a gravel terrace around 50m north of the Keltie Water. It has been much disturbed over the years with material robbed for building work, field clearance material added, and a road and a couple of track cut across it.

The cairn stands to a height of approximately 0.5m, although it is taller at either end (possibly partly due to the addition of field clearance material). The south-south-east end has been interpreted as a separate chambered cairn of the Clyde type measuring around 48m in length by around 15m across and up to 1.6m in height. Large stones built into the earth probably form a concave entrance into a chamber, the stones of which can be seen within the cairn material.

The cairn is thought to have been extended with the addition of stones running a further 300m to the north-north-west. Around 118m along the cairn from the south-south-east the remains of a second chamber can be seen, with the side slabs and head stone still in place and the entrance on the west side.

At the north-north-west end the cairn measures around 11m across.