Pen yr Helgi Du

Ffynnon Llugwy (English: Llugwy spring) is a lake in the Carneddau range of mountains in Snowdonia, North Wales. It lies at a height of about 1,786 feet (544 m) and covers an area of some 40 acres (16.19 ha). It has a maximum depth of 146 ft (45 m).Since the early twentieth century water has been taken from its outflow, Afon Llugwy to feed Llyn Cowlyd via a series of leats. Since the mid 1970s the lake has additionally acted as a reservoir for Bangor and eastern Anglesey, which necessitated the laying of an 11-mile pipeline to the water treatment works at Mynydd Llandegai.It is the source of the River Llugwy (Welsh: Afon Llugwy) which flows via Capel Curig and Betws-y-coed before becoming a tributary of the River Conwy.

Llyn Llyffant is the highest lake in Wales, located at grid reference SH 687 645. Its name translates into English as "frog lake". It lies at an elevation of approximately 815m above sea level.

Llyn Melynllyn (Welsh for yellow lake) is a lake within the Carneddau range of mountains in Snowdonia, North Wales. It lies at a height of just over 2,000 feet (610 m), and has an area of some 18.5 acres (75,000 m2). Cliffs rise steeply from its western edge, up to the summit of Foel Grach, and down from which most of its feeder streams flow. A small dam was built at its northern end in 1887, but this was deliberately breached in 1970. The lake acts as a reservoir for the Llandudno area. Less than a kilometre to its north lies the larger Llyn Dulyn. The outflow from the lake is called Afon Melynllyn, this stream flowing north-east to join Afon Dulyn, itself a tributary of the river Conwy.

Carnedd Llewelyn, also spelled Carnedd Llywelyn, is a mountain massif in the Carneddau range in Snowdonia, north-west Wales. It is the highest point of the Carneddau and the second highest peak by relative height in Wales, 49th in the British Isles and lies on the border between Gwynedd and Conwy.

Pen Llithrig y Wrach is a mountain peak in Snowdonia, Wales. It is one of the four Marilyns that make up the Carneddau range. To the east is Creigiau Gleision, another Marilyn, while to the west is Pen yr Helgi Du and Carnedd Llewelyn. Craig Eigiau and Llyn Eigiau can be seen to the north, while Gallt yr Ogof, Glyder Fach and Tryfan can be viewed to the south. It has one of the more colourful names of any British mountain, translating as slippery peak of the witch, perhaps in reference to the boggy conditions underfoot, or because of the resemblance of its pointed profile to an archetypal witch's hat. It is an outlier of the Carneddau, the higher peaks of which can be reached from Pen Llithrig y Wrach via Pen yr Helgi Du. On its eastern side, the mountain slopes steeply down to Llyn Cowlyd. It may be climbed from the southern side, from Capel Curig or the A5, or from the north-east, from Dolgarrog or Tal-y-bont in the Conwy valley. It is quite prominent when viewed from the north near Llandudno.

Foel Grach is a mountain in the Carneddau range. It is the eighth-highest summit in Snowdonia as well as Wales, and is included in the Welsh 3000s. It is located on a broad ridge extending northwards from Carnedd Llewelyn to Carnedd Gwenllian (formerly Y Garnedd Uchaf) and Foel-fras. An emergency refuge has been built below the summit. Compared to the surrounding mountains, much deeper snow settles here due to its rather broad summit and high grassy slopes. On clear days the Isle of Man and even the Mourne Mountains in Northern Ireland can be seen from the summit.

Llyn Dulyn (Welsh: black lake) is a lake on the edge of the Carneddau range of mountains in Snowdonia, North Wales. The lake is 33 acres (130,000 m2) in extent and 189 feet (58 metres) deep. Less than a kilometre to its south lies the smaller Llyn Melynllyn. Cliffs rise steeply from the lake edge up to the summits of Garnedd Uchaf and Foel Grach, giving it a dark brooding appearance - hence its name. The lake was dammed in 1881, to increase its capacity, and was significantly altered in 1931 by Llandudno Waterworks.As a reservoir Dulyn (along with Melynllyn) provided water for the town of Llandudno. The reservoir was repurposed in 1997 for use as hydroelectric generation. The outflow from the lake, the Afon Dulyn, also feeds water into neighbouring Llyn Eigiau. Afon Dulyn flows north-east, passing Tal-y-bont before joining the River Conwy. The cwm has been the site of a number of aeroplane crashes including that of an American Dakota aircraft which crashed into the cliffs above the lake in 1944 killing all four crew.

Llyn Cowlyd is the deepest lake in northern Wales. It lies in the Snowdonia National Park at the upper end of Cwm Cowlyd on the south-eastern edge of the Carneddau range of mountains, at a height of 1,164 feet (355 m) above sea level. The lake is long and narrow, measuring nearly 2 miles (3 km) long and about a third of a mile (500 m) wide, and covers an area of 269 acres (1.1 km2). It has a mean depth of 109 feet (33 m) and at its deepest has given soundings of 229 feet (70 m), this being some 45 ft (14 m) greater than its natural depth, the water surface having been raised twice by the building of dams.The surrounding hills drop steeply to the water's edge, from Cefn Cyfarwydd and Creigiau Gleision to the east, and Pen Llithrig y Wrach to the west, and as a consequence have not been forested in the 20th century, as were the slopes of neighbouring Llyn Crafnant. Indeed, there is not a tree to be seen, and the general aspect is one of bleakness. Dependent on the weather conditions, the waters often appear dark. The supply of water to Llyn Cowlyd is assisted at its south-western end by a leat which runs roughly east–west along the 1370-foot contour to the south and west of the lake, along the Llugwy valley. It is also fed by water from Llyn Eigiau. Llyn Cowlyd can be reached by road from Trefriw, some 3 miles (5 km) to the east, although the metalled road stops at a gate, the best part of a mile from the lake itself, beyond which private vehicles are not permitted. Llyn Cowlyd can also be reached by foot from Capel Curig, some 2 miles (3 km) away, from the ridge of Cefn Cyfarwydd, or from above Dolgarrog. A good path runs along the north-western shore of the lake. The stream which flows from Llyn Cowlyd is called Afon Ddu. This flows into the river Conwy, passing Pont Dolgarrog on the B5106 road, just south of the village of Dolgarrog. The gorge cut by the river at this point is popular for gorge walking.

Afon Eigiau is a small river in the Carneddau mountains in Snowdonia, in north-west Wales, which flows down Cwm Eigiau and into Llyn Eigiau.It is fed by smaller streams which flow down the slopes of neighbouring Foel Grach, Carnedd Llywelyn and Pen yr Helgi Du.

Llyn Eigiau is a lake on the edge of the Carneddau range of mountains in Snowdonia, Conwy, Wales. The name Eigiau is thought to refer to the shoals of fish which once lived here. Early maps refer to it as Llynyga. It is thought that a small number of Arctic char exist in the lake (as they do in neighbouring Llyn Cowlyd) after they were transferred here from Llyn Peris, and certainly it is one of the few lakes in Wales to have its own natural brown trout. The lake is surrounded by mountains including Pen Llithrig y Wrach.

Gyrn Wigau is a summit of the Carneddau range in Snowdonia, Wales, and forms a part of the western Carneddau commonly known as the Beras. It is a top of Drosgl. It has only 15 metres of topographical prominence but is listed as a Nuttall.

Carnedd Gwenllian (named Y Garnedd Uchaf before 2009) is a minor summit of the Carneddau range in Snowdonia, Wales, and included in the Welsh 3000s. From the summit, distant views to the north can extend as far as Ireland and the Isle of Man, and to the South as far as the Berwyn Ranges. It lies between Foel Fras and Foel Grach, but is not always included in the Welsh 3000s, as its summit rises only slightly above the ridge. However, it is classed as a Hewitt. Its slopes, like all those in the northern Carneddau, are largely grassy, although they are steep. The slopes can receive significant accumulations of snow-drifts during blizzards in winter. In the past, snow beds have survived on the mountain as far as June. The annual average temperature on Y Garnedd Uchaf is relatively cold, ranging between 4-5 degrees Celsius.For some years there was a campaign by the Princess Gwenllian Society to have the name of this peak changed from Y Garnedd Uchaf to Carnedd Gwenllian. Gwenllian of Wales (1282–1337) was the only daughter of Llywelyn ap Gruffudd. After her father's death, she was held in a nunnery at Sempringham in Lincolnshire until she died. In September 2009, the summit was renamed Carnedd Gwenllian, and the Ordnance Survey agreed to use the dual name Carnedd Uchaf/Carnedd Gwenllian on its maps from 2010 onwards.