Mwdwl-eithin (Marilyn) & Alwen Reservoir Circuit

A walk to bag a Marilyn with little ascent and a circuit of Alwen reservoir through forest and open land.

Blue

7 September 2025

No dogs allowed

Leaving the CP at the reservoir dam, we go through the forest climbing steadily on forest tracks and roads. After exiting the forest we follow the trail to find an unmarked path to ascend Mwdwl-eithin. At the top there is a section of (removed) barbed wire fence to step over to reach the summit.

We retrace our steps to descend then follow the track to a bridge over the reservoir, returning along the reservoir via forest tracks/road

Terrain:
Mainly easy walking on a mix of forest, paths, tracks, gravel & open land. The ascent/descent of the Marilyn is over uneven, open, land with some bracken (gaiters advised)
Map/Area:
Explorer 264 Vale of Clywd
Starting Point:
Alwen Resevoir Dam CP, LL21 9TU (off B4501) GR SH956529 Note: CP is £2.50 CASH ONLY
What3Words:
///hunches.diverged.shelters
Walk Starts:
09:15
Walk Finishes:
14:00
Distance:
13.6km
Ascent:
214m
Highest Point:
Mwgwl Eithin 532m

Safety

Let the walk leader know of any relevant medical conditions

Refer to the Handbook for walk related information and specifically for recommended walking equipment and safety information

Remember you are responsible for being properly equipped

Ensure you have the walk leader’s phone number in case of an emergency

If you become detached from the group STOP, call out; try contacting group by phone or text. If no contact return to the last place you were with the group. Wait 30 mins repeatedly trying to make contact. After 30 mins seek help and/or make your own way safely.

The Google map below is the location of the walk start point.