Visited 4th January 2003: Llech Bron is on private land, but you can see it clearly from the road. William and I bumped into the woman who owns the land while I was gawping at the stone, and we chatted by the roadside for a while. She was very friendly, but wasn't keen for us to go up to the stone because there were rams in the field (and it was muddy - not sure why she thought this was problem though). She invited us to come back in the summer to take a closer look.
From our conversation I learned an found out a variation on the legend that Rhiannon has posted (below). Apparently while he was making Devil's Bridge the Devil threw the stone from "that hill over there" (presumably Trichrug).
Another story she told me is that a local farmer tried digging down the side of the stone with his tractor. Apparently he got 30 feet down, and still didn't find the bottom of the stone.
I'm a bit suspicious about the tractor story, but the Devil story sounds about right. I was also told that the name Garreg y Big is used affectionately by the locals to describe the stone.
This is a pretty big stone - 14 ft tall - but it only seems to be on the old Ordnance maps? Chris Barber's 1986 book 'More mysterious Wales' has a photo, so surely it can't have disappeared?
You may have been to Devil's Bridge? Well the devil was collecting stone for this over on the top of Trichrug Mountain. He'd bit off a bit more than he could chew with this huge stone, so sat down for a bit of a rest. He'd been gripping it so hard that his fingers left marks in the stone (can you see them?). He was just drifting off into a nice nap when a cockerel patrolling the field spotted him, and sneaking up behind gave a deafening crow. The devil leapt to his feet in surprise and ran off, leaving the stone behind. Where you'll (hopefully) find it today.
Nearby, in the Brynarian caravan park, is another stone which I went to investigate. I'm pretty convinced that it's an old gatepost. It has a hole running through it, and it's extremely rectangular. I've not given it a site of its own. I should mention that proprietor of the caravan park was extremely friendly, and didn't mind me taking a look at the stone.
I'm told that there's a third stone nearby, but I have yet to find it. I have no idea how old this one is.