Gilwern Hill, Powys should not be confused with Gilwern Hill, Monmouthshire.
Gilwern Hill is a hill about 3 mi / 5 km southeast of Llandrindod Wells in the county of Powys, Wales.
The hill is composed from a range of lower and middle Ordovician volcaniclastic rocks which form a part of the Builth Inlier. Palaeontologists Pete Lawrance and Brian Beveridge have spent 30 years examining fossils from a privately owned limestone quarry on the hill. Amongst fossils so far identified at this location are the trilobites Meadowtownella, Bettonolithus, Protolloydolithus and Anebolithus together with Conulariida, Iocrinus, Clonograptus and starfish[1]
There are two prehistoric stone rows at the southern end of the hill, each with a large stone, more than 2m high, at one end.[2]