Carnedd Llewelyn

Overview

Carnedd Llewelyn, also written Carnedd Llywelyn, is the highest summit of the Carneddau in Eryri, Wales. The Database of British and Irish Hills v18.6 records 1,061.8 m, with 747.5 m prominence. It is the third-highest Welsh summit in that dataset, after Yr Wyddfa and Crib y Ddysgl (Garnedd Ugain). Older guides commonly give 1,064 m. DoBIH

Summit and terrain

The summit is a cairn on a broad stony plateau. Its detailed grid reference is SH 68364 64375. DoBIH distinguishes a nearby lower shelter from the summit cairn. Several ridges leave the plateau, so use map-and-compass navigation in cloud. Approaches combine rock, loose slopes, grass and bog; they are substantial mountain outings.

Geology and name

BGS places the area in the Ordovician volcanic terrain associated with the Llewelyn Volcanic Group and records tuff on the mountain’s north side. Granite and slate are not an adequate summary. BGS

The name means “Llywelyn’s cairn”. Traditions differ between Llywelyn ap Iorwerth and Llywelyn ap Gruffydd. Hugh Derfel Hughes’s 1864 Llawlyfr Carnedd Llywelyn reflects the mountain’s long cultural importance. The name does not establish a prince’s burial on the summit. Carneddau Landscape Partnership

Choosing a route

The route cards summarise five distinct itineraries:

• An Ogwen circuit from the east end of Llyn Ogwen, over Pen yr Ole Wen and Carnedd Dafydd, returning past Ffynnon Llugwy
• An A5 approach via the Ffynnon Llugwy reservoir road and Bwlch Eryl Farchog, retraced for an out-and-back
• A long Cwm Eigiau circuit over Foel Grach, Carnedd Llewelyn, Pen yr Helgi Du and Pen Llithrig y Wrach
• A Gerlan scrambling circuit over Crib Lem, Carnedd Dafydd, Carnedd Llewelyn and Yr Elen
• A Gerlan horseshoe ascending Yr Elen and returning from Carnedd Dafydd over Mynydd Du

These summaries are not turn-by-turn navigation. Plan the entire route and return. The Ogwen and southeast approaches include rock steps; Crib Lem is a Grade 1 scramble. The Gerlan horseshoe has bog, loose ground and a river crossing. There is no basis here for promising a waymarked northern route or general beginner suitability. Ogwen circuit · Gerlan horseshoe

Access and facilities

Bethesda/Gerlan and the Ogwen valley are useful bases. Use designated parking without obstructing roads or farm access. The reservoir approach begins on the A5; do not assume public vehicle access to Ffynnon Llugwy. Cwm Eigiau has a remote road-end parking area. Ogwen Centre provides toilets, drinks and snacks; carry supplies for the mountain. Eryri: Ogwen

The T10 serves Bangor, Bethesda, Ogwen and Betws-y-Coed. Check current stops, timetables and the last return. Avoid relying on historic bus names or published parking prices.

Safety and responsible access

Check the mountain forecast, carry suitable clothing, navigation equipment, food and water, and leave a route plan. Cloud, high winds, crags and a wrong summit exit can create serious difficulties. Rain makes loose rock and streams more hazardous. Snow, ice and cornices require appropriate winter skills and equipment. In a mountain emergency call 999, ask for Police, then Mountain Rescue. Eryri safety advice · Ogwen Mountain Rescue

Keep dogs under control and on a short lead around livestock. On open access land use a lead no longer than 2 m from 1 March to 31 July. Wild camping requires prior permission from the landowner or farmer. Dogs · Camping