The square-bricked tomb in the woods of Glentrool commemorates six Covenanters who were surprised while praying and shot on the spot. There is a plaque and carved stone within the walled enclosure and a large stone placed on the four outside walls to enable people to view inside.

The Covenanters were Scottish Presbyterians who objected to English Anglican interference in their worship.  The name Covenanters comes from the fact they supported the National Covenant of 1630, which pledged opposition to the English bishops. When Charles II was restored to the throne in 1660, many ministers left their parishes and held illegal open-air conventicles. Troops were sent in and violence erupted.

This period is known locally as the "Killing Times." One of the main persecutors of the Covenanters was "Bloody Clavers." Hundreds of Covenanters marched towards Edinburgh but were dispersed at the Battle of Rullion Green in the Pentland Hills in 1666. The Covenanters were then routed again at Bothwell Bridge in 1670, and again in 1680 at Airds Moss near Cumnock. Then in 1688 William and Mary came to the throne and in an attempt to unite the country relaxed the laws causing the area to become more peaceful.