Visited summer 1991: I can only dimly remember this visit, and unfortunately I was totally oblivious to the stone circle and cairns at the time. Either that or we stumbled across the stone by chance. I know I was impressed by the size of the thing, but I wish I'd paid more attention.
"The impressive standing stone at Strontoiller is a rough-cut pillar, standing some thirteen feet high, which was used in healing rituals. It is said to mark the grave of Diarmid, the mythical hero. The adjacent cairn was excavated and some cremated bone was found. Quartz chips and pebbles were found under the kerbstone: quartz is often associated with burial sites in the west."