Clach nam Breatann
The Clach nam Breatann (or Minvircc) is a large stone which marked the boundary between Dál Riata, Alt Clut and the homeland of the Picts in what is now Scotland . The Stone still stands, on the slopes of Glen Falloch, between Crianlarich and Inverarnan. The base circumference is  and height . There is another boundary stone in Ben Donich, called Clach A' Bhreatunnaich. References

Scotland in the Early Middle Ages
Boundary markers