The Kempock Stone, or Granny Kempock, stands on a cliff above Kempock Point on the Clyde Estuary. The stone is about 1.8m tall and 0.8m in diameter (6 feet tall, 2 feet in diameter) and of an unusual shape said to resemble a bent and cowled old woman (the eponymous Granny Kempock).

It is presumed to be Bronze Age, but I am not aware of any dating evidence to confirm this. There is a lot of graffiti carved into its surface - mostly initials from the 1600s onwards. Also a hole has been drilled into the lower part of the stone - it is unclear how deep it goes or whether it passes all the way through. But also some symbols that have been suggested to be masons marks, which perhaps indicates that the stone might not be an ancient monument but may have come from a more recent structure such as the nearby Gourock Castle (now gone, the last of it being demolished in the 1700s).

There was a superstition that sailors would perform rituals at the stone to ensure fair winds, and newly-weds would pass around the stone to bring the marriage luck.

In 1662 a group of 6 women were tried for witchcraft, being accused of dancing around the stone and attempting to throw it into the sea. One of them, Marie or Mary Lamont, was notable for only being 16 when she was "persuaded" to confess and was burned to death as a result.

The stone also features in one of the better written and better acted childrens' TV shows relating to standing stones - 1987's The Shadow of the Stone, with early starring roles for Shirley Henderson and Alan Cumming.