It is a horsetail style set of falls which are located in the Cambrian Mountains about 2+1⁄2 miles (4 kilometres) from Glaspwll in Powys, Wales.

It is formed where the River Llyfnant falls from Llyn Penrhaeadr for approximately 525 feet (160 metres) into Cwm Rhaeadr in two waterfalls, and a series of cascades.

[7] The large horsetail cascade alone surpasses the 73m-tall Pistyll Rhaeadr by a significant margin, in turn slightly surpassed by the 93m high Devil's Appendix and the 160-180m high Nant Maesglase waterfall, which is likely the tallest in Wales.

However, all 3 of these waterfalls with the possible exception of Pistyll y Llyn have markedly low water flow at nearly all times, and may not run at all during the summer months.

In 2020, most of the land between the waterfall and the village was converted into an intensely managed pheasant shoot.