Grey Mare's Tail

The Grey Mare’s Tail is a waterfall near Trefriw on the edge of Snowdonia National Park. It sits beside the B5106 road between Llanrwst and Trefriw, close to Gwydir Castle. The Welsh name Rhaeadr y Parc Mawr means ‘waterfall of the great park’ because the stream comes from Gwydir Forest through the old Parc Mine. Lady Willoughby of Gwydir Castle gave it the English name, inspired by Lord Byron’s comparison of a Swiss waterfall to a grey mare’s tail. The falls are fed by a large stream that flows underground for much of its course before emerging near the site. The waterfall is unusual because it has two separate cascades that split around a large rock at the top. In 1895 a postcard called it the White Mare’s Tail Cascade, showing only one fall, but the setting matches today’s location. Below the falls is a shallow plunge pool where the water collects before passing under the road into the River Conwy. The woodland around the falls, Coed Felin Blwm, once housed a lead mill built by the Gwydir Estate to crush ore from Parc Mine. Later the mill became a sawmill, and both lead and timber were floated down the River Conwy from Trefriw. The area is now a nature reserve managed by Natural Resources Wales, part of a larger protected landscape that includes Gwydir Forest. A small car park marks the start of the walk, but there are no signs to advertise the falls, so many passers-by miss it. The water is not pure because it carries minerals from the forest rocks, and the spray can feel sharp even in summer. A leat once took water from above the falls to power a fountain in Gwydir Castle’s gardens, a system that still works today. Visitors can reach the falls either from the roadside or by walking down from the lane above to Llanrhychwyn.