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Llyn Cwellyn – Caernarfon Castle loop from Groeslon

Llyn Cwellyn – Caernarfon Castle loop from Groeslon

Moderate

riders

Llyn Cwellyn – Caernarfon Castle loop from Groeslon

02:32

54.8km

510m

Road cycling

Moderate road ride. Good fitness required. Mostly well-paved surfaces and easy to ride. The starting point of the route is right next to a parking lot.

Last updated: July 17, 2026

Tips

Includes a segment in which cycling is not permitted

After 36.8 km for 102 m

Waypoints

Start point

Parking

Get Directions

257 m

Coed y Garth

Forest

6.39 km

View of Snowdon (Yr Wyddfa) Across Llyn Nantlle Uchaf

Highlight • Viewpoint

Nantle Valley is well known for its mountains and ridge. A lot of historic settlements and slate mining. Stunning views of Snowdonia. Road surface is good watch out for sheep moving freely and a couple of cattle grids in this area

Tip by

10.5 km

Drws y Coed Climb

Highlight (Segment) • Climb

A 4.3km climb in Dyffryn Nantlle with a deceptive average gradient of 3.3% with the final section closer to the maximum gradient of 12.4%.

A 4.3km climb in Dyffryn Nantlle with a deceiving average gradient of 3.3% as the final section is much closer to its 12.4% maximum gradient.

Translated by Google •

Tip by

12.0 km

View of Y Wyddfa

Highlight • Other

15.4 km

Llyn Cwellyn

Highlight (Segment) • Natural Monument

Llyn Cwellyn is a reservoir in North Wales which supplies drinking water to parts of Gwynedd and Anglesey. It lies on the Afon Gwyrfai in Nant y Betws between Moel Eilio and Mynydd Mawr in the northern part of Snowdonia National Park. It has an area of 215 acres, and is over 120 ft deep.
It has amazing views well worth a stop.

Tip by

18.2 km

Coed Plas-y-nant

Forest

27.2 km

Old Railway Tunnel

Highlight • Structure

the old railway line is flat and gets you off the main road.

Tip by

36.2 km

Caernarfon Castle

Highlight • Monument

Royal fortress-palace built on legends and bitter medieval conflict Caernarfon Castle is recognised around the world as one of the greatest buildings of the middle ages

Tip by

36.4 km

Caernarfon Castle

Highlight • Castle

A medieval fortress situated on the on the banks of the River Seiont, Caernarfon Castle has protected Caernarfon since the 11th century. The magnificent castle is open to visitors from 9.30am - 5pm (last admission at 4.30pm). Tickets costs £9.90 for adults. You can find out more information about events at the castle here: cadw.gov.wales/daysout/caernarfon-castle/?lang=en

Tip by

36.9 km

View of Caernarfon Castle

Highlight • Historical Site

Castell Caernarfon is recognised around the world as one of the greatest buildings of the Middle Ages.

This fortress-palace on the banks of the River Seiont is grouped with Edward I’s other castles at Conwy, Beaumaris and Harlech as a World Heritage Site. But for sheer scale and architectural drama Caernarfon stands alone.

Here Edward and his military architect Master James of St George erected a castle, town walls and a quay all at the same time. This gigantic building project eventually took 47 years and cost a staggering £25,000.

The castle was born out of bitter war with Welsh princes. So of course its immense curtain walls and daunting King’s Gate were designed to withstand assault. But the polygonal towers, eagle statues and multi-coloured masonry sent a more subtle message.

Tip by

54.8 km

End point

Parking

Way Types & Surfaces

Way Types

40.7 km

11.7 km

2.08 km

267 m

122 m

Surfaces

42.6 km

12.1 km

164 m

< 100 m

Elevation

Nothing selected – click and drag below to see the stats for a specific part of the route.

Highest point (240 m)

Lowest point (0 m)

Weather

Thursday 16 July

24°C

12°C

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Llyn Cwellyn – Caernarfon Castle loop from Groeslon

View of Snowdon (Yr Wyddfa) Across Llyn Nantlle Uchaf

Drws y Coed Climb

View of Y Wyddfa

Llyn Cwellyn

Old Railway Tunnel

Caernarfon Castle

Caernarfon Castle

View of Caernarfon Castle

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