Tre’r Ceiri & Yr Eifl Hillfort Walk, Llyn Peninsula

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Difficulty: Hard

Length: 6.59 km (4.1 miles)

Approx. duration: 2:30-3:30hrs

Parking: Free (Google Maps)

Dogs: Yes – On lead near livestock

From Perthi Holiday Cottages: 45 minute drive from our cottages.

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Ruined Iron Age roundhouses at Tre Ceiri, Llithfaen

This rewarding circular walk explores the upland slopes of Yr Eifl and the exceptionally well-preserved Iron Age hillfort of Tre’r Ceiri, combining archaeology, open moorland, and wide coastal views on the Llŷn Peninsula.

You're in the right place if you're looking for a moderate walk with steady climbs and expansive views. The ground underneath Yr Eifl can be very boggy in places — proper waterproof boots are essential rather than optional here.

Set high on the hillside beside Yr Eifl, Tre’r Ceiri is one of Britain’s finest surviving Iron Age hillforts. Dating back more than 2,000 years, the site contains remarkably intact stone round houses, gateways, and defensive walls, offering a rare and atmospheric glimpse into prehistoric life.

From the hillfort, the walk continues across open upland ground towards the summit area of Yr Eifl. Although the landscape feels spacious and remote, the gradients remain manageable, making this an enjoyable rather than strenuous mountain walk.

The views from higher ground are extensive, taking in the coastline of the Llŷn Peninsula, the Irish Sea, and the mountains of Snowdonia to the east. On clear days, the sense of openness and light is one of the highlights of the walk.

After the walk, it’s worth driving down to the secluded village of Nant Gwrtheyrn, a former quarrying settlement now home to a Welsh language centre. Caffi Meinir there is a lovely stop for coffee or lunch, and there’s a quiet beach to walk off the last of the day.

“This is our favourite walk outside the Eryri National Park — it’s so varied and the Iron Age roundhouses at Tre’r Ceiri are genuinely remarkable, some of the best preserved in Britain. One thing to be prepared for: the ground right underneath Yr Eifl can be very boggy, proper boots make a real difference. And if you can, go down to Caffi Meinir in Nant Gwrtheyrn afterwards — it’s a beautiful spot and a lovely way to finish the day.” — Delyth, Perthi Holiday Cottages

Our 17th-century cottages sit just above Beddgelert, with walking routes straight from the door.

Step-by-Step Walk Guide

Numbered steps with photos to help you follow the route.

The car park can be found above the village of Llithfaen and Nant Gwrtheyrn. To begin the walk, cross the main road and the bridle path, then take the path that cuts east through the heather. This path takes you to the right of the Eifl hill that you see in front of you. Do not take the bridle path heading north-east, as this will be used for the descent later in the walk.
Keep following the track through the heather, keeping Yr Eifl on your left. The path splits at certain times. In the pictured photo take the right hand split, don't ascend Yr Eifl yet.
Keep following the path aiming uphill for the rocky outcrop seen in the picture. This path leads you to a kissing gate at the brow of the hill.
At the brow of the hill you will see the hillfort of Treceiri. Keep following the path and go through a second kissing gate. You are aiming for the gap between the Eifl and Tre'r Ceiri.
Follow the path all the way up to the plateau between Yr Eifl and Tre'r Ceiri. Here at the crossroads take the right turning towards Tre'r Ceiri and go up to the hillfort through the old gate. Here you can meander around the sight before returning to the main gate.
After returning to the main gate, descend back to the crossroads and take the path that leads up to Yr Eifl opposite Tre'r Ceiri. The path gets very boggy here for about 80 meters.
After the boggy part you will arrive at a gate. Go through the gate and keep following the path upwards between the rocks and heather.
After arriving at the top, climb the mound of rocks to get to the summit.
Descend the mound northward to find the path that descends north westerly down Yr Eifl. The path is steep and rocky here so take care.
Keep following the path north westerly downhill towards the hill opposite (there is a mast on this hill).
It is also possible to ascend the hill from this point (pictured). However, at the crossroads by the electricity pole we took the left-hand turning (south-westerly), which leads down the bridle path and returns you to the car park.

17th-Century Cottages in Beddgelert

Rated 4.98 on Airbnb from over 300 guest reviews

Ty Hebog historical barn conversion exterior at Perthi in Beddgelert Cosy log burner interior at Ty Hebog cottage Luxury king size bedroom with original historic character at Ty Felin water mill

Stay in a converted water mill, a historic barn or a mountain lodge on Delyth’s family farm above the village — with wide Eryri views and walking routes from the door.