A single cairn lies to the southwest of the rest, separated from them by both a stream and a trackway running east-west between two tumbled stone walls. Tracing the field shapes on the OS map tells us where this cairn should be, but we can’t see it (or at least we can’t recognise it). There is no defined path down from the ridge, so we head straight down through the scrubby vegetation to where the cairn should be, next to a small triangular field.
And so it proves to be. The cairn is actually very large, at least its footprint is. But it is covered in grass and heather, seemingly set on blending into the landscape. It could be a ring cairn, as little remains beyond the circular bank of rubble that defines its outer edges. Perched on a little knoll, next to a clear-running stream, it positioning reminds me of the cairn across the stream from Maen Llia in the Brecon Beacons, far, far away to the south.
I didn't see this cairn on my first visit, but as it's part of the collective round these parts we put that right.
As the name suggests it's southwest of the main group, across the hard going sea of grass that reminds one of Rohan from the lord of the rings.
We came at it from the hill fort of Craig y Castell to the south, even from above it was still hard for me to spot it, but more obvious at ground level.
It is not a stoney spread like the other two, but a grassed over cairn of a good size, with the odd bit of cairn material poking through. Cader idris itself is not visible from it but the cairns of Tyrrau Mawr are and down the valley to Pared y Cefn Hir.