Cirein Fhionn Lochan, Meall Biorach and Coirein Lochain

This is a compact but demanding hill circuit on Arran’s quieter northwest side, climbing from near Thundergay, just north of Pirnmill, into a dramatic corrie landscape of rough grass, stone path, small waterfalls, and open ridges before visiting the heights around Meall Biorach and Coirein Lochain. Expect roughly 9 km / 5.6 miles with about 600 m / 1,970 ft of ascent, which is a serious amount of climbing for the distance and explains the difficult rating. The route is short on mileage but not short on effort: the gradients bite, the terrain can turn wet and boggy, and the upper ground is exposed to wind and mist. (walkhighlands.co.uk)

The start is best described as the roadside access at Thundergay, near Pirnmill, Isle of Arran, where the improved hill path heads inland past cottages and through a gate. Some longer traverses in the area finish here and then use the shore road back to Pirnmill, but for a shorter outing focused on Coire Fhionn Lochan, Meall Biorach and Coirein Lochain, this is the most practical access point. (walkhighlands.co.uk)

The first section usually feels straightforward underfoot thanks to the constructed path, but it gains height steadily beside the Uisge Soluis Mhòir. After about 1.5 to 2 km / 0.9 to 1.25 miles, the route begins to reveal the corrie more fully, with the slopes of Meall Bhig, Meall nan Damh, and Meall Biorach opening ahead. The pathwork here is one of the route’s advantages: it helps on the steeper ground, especially where the burn tumbles down in a series of attractive cascades. Even so, after rain the stones can be slick, and the surrounding ground can be saturated. (walkhighlands.co.uk)

Terrain and route character

At around the halfway point of the outward climb, Coire Fhionn Lochan comes into view, tucked into a high corrie and often noted for its pale, stony shoreline and strikingly clear water. This lochan is the visual centerpiece of the walk and one of the most memorable mountain waters on Arran. The setting is unusually dramatic for such a modest-distance route: a compact bowl of hills, steep enclosing slopes, and long outward views west across the Kilbrannan Sound toward Kintyre, with the Paps of Jura sometimes visible in clear weather. (walkhighlands.co.uk)

From the lochan, the route becomes more serious. Any climb toward Meall Biorach and the rim above Coirein Lochain involves steeper, rougher ground than the lower approach. The upper slopes are broad rather than technical, but they can feel confusing in poor visibility because the summits are rounded and the corrie edges are not always obvious until you are close to them. In clear weather, the ridgeline gives wide views over northern Arran, the sea to the west, and the larger Arran mountain group inland. In mist, this same openness can make navigation awkward, so carrying and knowing how to use HiiKER is sensible for tracking the line of ascent, the corrie edge, and the descent back toward the lochan. (walkhighlands.co.uk)

The descent is where many walkers need to stay disciplined. The ground dropping back