Maen Llia is a standing stone which sits on moorland at grid reference SN924192 in the Brecon Beacons National Park in Powys, Wales.
The stone which is a large piece of intraformational conglomerate from the Old Red Sandstone measures 3.7 m high by 2.8 m wide by 0.6 m. It is roughly diamond-shaped and is partly moss-covered. Its age and original purpose are unknown though it is thought to date from the Bronze Age. It is a popular tourist attraction, lying just 30 yards off a minor road running north from the village of Ystradfellte in the Waterfall Country towards the hamlet of Heol Senni and Brecon, the county town of Brecknockshire.
There is a low heather-covered henge 200 metres to the southwest. Another significant standing stone, Maen Madoc, lies just off the old Roman road known as Sarn Helen about 2 miles to the south.
Wikipedia https://en.wikipedia.org/wiki/Maen_Llia
Address Sarn Helen, LD3 8, United Kingdom
Coordinates 51°51'39.122" N -3°33'49.265" E