Just to the north of Sannox is a signposted turning for a forestry commission picnic / camping area. Follow this narrow road until you reach the car park at the end. The cairn is right next to the car park - can't miss it.
Strangely enough the info board at the car park makes no mention of the cairn.
The cairn is approximately 3 metres high x 25m across. The mound has many large stones scattered all around and on top of it amid the long, rough grass. One of the stones lying on top looks like a giant arrowhead! On top of the cairn is a 'standing stone' made up of lots of pretty pink quartz pieces.
This is a nice cairn in a nice spot. Dominated by the surrounding mountains of north Arran.