Holyhead Mountain, North Stack and South Stack Cliffs Loop

This medium-difficulty coastal loop packs a lot into roughly 7 km / 4.3 miles, with about 300 m / 985 ft of ascent: sea cliffs, heathland, old quarry ground, a mountain summit, a lighthouse, and some of the most dramatic cliff scenery on Holy Island near Holyhead, Anglesey. The route is usually associated with the Breakwater Country Park side of Holyhead Mountain and the cliff paths linking North Stack and South Stack, with Holyhead Breakwater Country Park being the most practical start point for a loop of this length. That places the hike head near Holyhead Breakwater Country Park, Holyhead, Isle of Anglesey, LL65 area, at the foot of Holyhead Mountain. Breakwater Country Park has parking and visitor facilities, while South Stack also has parking, toilets, and reserve facilities if you choose to begin there instead. (alltrails.com)

The walking is varied rather than relentlessly steep. Expect a mix of stony tracks, rough coastal paths, short sharper climbs, and uneven rocky sections where footing needs attention, especially in wet or windy weather. Although the overall distance is modest, the terrain makes it feel more substantial than a simple 7 km outing. The ascent is concentrated in bursts as the route rises from the lower quarry and cliff-edge paths toward Holyhead Mountain, which reaches about 220 m / 722 ft above sea level. (holyhead.org)

What the route feels like

From the country park side, the opening section usually eases hikers in with broad paths and quarry-edge walking before the landscape becomes wilder and more exposed. The old quarry beneath the mountain is a reminder that this area once supplied stone for Holyhead Breakwater, and the terrain quickly shifts from industrial heritage to open coastal drama. As the route bends toward North Stack, the ground becomes rockier and the views widen across broken cliffs, sea inlets, and offshore stacks. (holyhead.org)

The stretch between North Stack and South Stack is the visual highlight for many walkers. Here the path runs through exposed cliff country with constant sea views and a real sense of height above the water. In windy conditions this section demands care, not because it is technical in a mountaineering sense, but because the edges are abrupt and the gusts can be strong. Good footwear is important, and this is not a route for casual beach shoes. If visibility is poor, keeping track of junctions on HiiKER is especially useful around the mountain paths and connecting tracks. (holyhead.org)

South Stack is the best-known landmark on the loop. The lighthouse stands on a small island just offshore and was completed in 1809 to help ships navigate this hazardous stretch of the Irish Sea on the busy route between Dublin, Holyhead, and Liverpool. The cliffs around it are high, rugged, and deeply cut, and the descent toward the lighthouse area adds a dramatic change of perspective after the higher mountain ground. (trinityhouse.co.uk)

Landmarks, wildlife, and history

Holyhead Mountain itself is the highest point on Anglesey, and even though it is only 220 m / 722 ft high, it rises so directly from the coast that it feels much bigger than the number suggests. Near the summit is Caer y Twr, a prominent ancient defended site later used as a Roman watchtower, and on the mountain’s lower slopes are the remains of prehistoric hut circles at Holyhead Mountain Prehistoric Village. That gives the walk unusual historical depth: within a few miles you pass evidence of prehistoric settlement, Roman-era occupation, 19th-century maritime engineering, and quarrying linked to the growth of Holyhead as a major port. (cadw.gov.wales)

The nature interest is just as strong. South Stack is an RSPB reserve where heathland and farmland meet sheer sea cliffs, and the area is well known for seabirds. Depending on season, hikers may see guillemots, razorbills, kittiwakes, and chough, with puffins sometimes noted offshore or around the wider cliff environment. Peregrines and ravens are also possible, and seals may be seen below the cliffs. Spring and early summer are especially rewarding for birdlife, while the heath and coastal vegetation add color later in the season. (rspb.org.uk)

Planning and access

By car, the easiest approach is to drive to Holyhead Breakwater Country Park on the western side of Holyhead, which is commonly used as a start for mountain and stack walks and has parking and basic visitor amenities.