Loch Lorsa, Loch Nuis, Beinn Nuis and Beinn Tarsuinn Loop

This is a big Arran mountain day that links glen walking, boggy moorland, rough ridge travel, and a long high-level circuit over Beinn Nuis and Beinn Tarsuinn before returning by the Glen Rosa side. At about 23 km / 14.3 miles with roughly 800 m / 2,625 ft of ascent, it sits in that awkward middle ground where the grade may be called medium on paper, but the terrain can make it feel harder than the numbers suggest. Expect a full day out rather than a quick half-day loop, especially if visibility is poor or the ground is wet. The route is in the northern Arran hills above Brodick, starting near the end of the public road by Glen Rosa Campsite, close to Glen Rosa, Brodick, Isle of Arran KA27 8DF, and the usual mapped start point is around grid reference NS 000 376. (walkhighlands.co.uk)

The opening section is comparatively gentle, following the good track into Glen Rosa with excellent views toward Goat Fell and the jagged skyline around Cìr Mhòr. After roughly 2 km / 1.2 miles, the route crosses the footbridge over the Garbh Allt and begins the real climb. From there, the character changes quickly: the path steepens beside the burn, then eases briefly across open moorland before becoming much rougher and wetter. Walkhighlands notes that the lower and middle sections can be very boggy and eroded, while the higher ground involves boulders, slabs, and sections where hands may be needed for balance. (walkhighlands.co.uk)

Terrain and what to expect

The climb toward Beinn Nuis is the first serious test. After the moorland section, the path becomes fainter in places and crosses wet ground before steepening onto rockier slopes. Around the 600 m / 1,970 ft level, the route improves somewhat, but it remains a mountain path rather than an easy hill track. The final pull to Beinn Nuis is steep and stony, and in mist it is easy to lose the best line if you are not paying attention. If you are planning navigation backup, use HiiKER for mapping and route tracking, but do not rely on a single device in poor weather. (walkhighlands.co.uk)

From Beinn Nuis, the ridge to Beinn Tarsuinn is one of the highlights of the day. The walking becomes more dramatic, with rocky undulations, broad views, and a stronger sense of exposure. Just before the summit area, look out for the Old Man of Tarsuinn, a natural rock outcrop shaped like a human profile looking out toward the sea over Brodick. This is one of the most distinctive landmarks on the circuit. Beinn Tarsuinn itself reaches 826 m / 2,710 ft and gives wide views across Arran’s northern mountains, the Firth of Clyde, and, on a clear day, much of the west coast beyond. (walkhighlands.co.uk)

The descent from Beinn Tarsuinn is often the crux of the loop. It is steep, awkward, and slower than it looks on a map, with boulders, rock steps, and short scrambling sections. Walkhighlands specifically warns against dropping too low toward the bealach on the airy lower path shown on some maps; the safer line stays on the clearer descending path from the ridge. This is the point where tired legs, wet rock, or strong wind can turn a moderate-feeling day into a serious one. If the weather is poor, allow extra time for this section. (walkhighlands.co.uk)

If your version of the loop continues over Beinn a’ Chliabhain before curving back toward Loch Nuis and Loch Lorsa, the ridge becomes somewhat gentler but still mixes grass, rock, and occasional easy slab crossings. The descent back toward Coire a’ Bhradain and the Garbh Allt is notorious for boggy ground, even after the steepest mountain terrain is behind you. That means dry feet are unlikely in