The Marchlyn Loop is a very popular walk in Eryri National Park with amazing views in all directions (on a good day!). You tick off four Nuttalls, two of which are Hewitts; Carnedd y Filiast North Top, Carnedd y Filiast, Mynydd Perfedd and Elidir Fawr. ​

The route can be walked in either direction, however we opted to walk clockwise and the views you have of Elidir Fawr are breathtaking. If you went anticlockwise, I feel like you would miss some of the magic.

The car park starts at the entrance to the power station site, which unfortunately means it is blocked with a locked gate. For roughly the first 1.5 miles, you slowly ascend a tarmac road to the edge of Marchlyn Mawr reservoir before turning left and following a well-trodden path up towards the first peak, Carnedd Y Filiast. If you want to tick off Carnedd Y Filiast North Top, take the left path half way up where the path splits and it is a short out-and-back to the summit (the All Trails route does not include Carnedd Y Filiast North Top).

The ascent to Carnedd Y Filiast is quite steep, however the path is clear. Towards the top, there is an optional scramble to the summit which is marked with a wind shelter. If you want to avoid this, head to the left-hand side to walk around and head towards Mynydd Perfedd.

The ridge towards Mynydd Perfedd is a gentle stroll with incredible views of the nearby peaks. You can spot the stone wind shelter in the distance which makes navigation straightforward. There is a large ladder stile, but there is a section of wall that is down if your dog struggles.

From Mynydd Perfedd, the views towards Elidir Fawr are quite daunting with the ridge looking very narrow and exposed, however it is not as bad as it looks. By this point you have already completed a large amount of elevation gain, but don’t let that fool you as the ascent to Elidir Fawr is still steep with a light bit of scrambling towards the summit. At the summit is another wind shelter which makes for a great spot for a short rest before you start your descent.

From the wind shelter, continue to walk along the top of the ridge before a clear path to the right become visible. This path will lead you to Elidir Fach before making a right turn back towards Marchlyn Mawr reservoir.

The descent is pleasant with plenty of natural step formations before you rejoin the tarmac road heading back down towards the car. The return leg is more enjoyable as you’re able to stretch off those legs!