An Caisteal

An Caisteal, at 995 metres, takes its name — "the Castle" — from a prominent rocky tor near its summit, and is one of the Crianlarich hills usually climbed together with neighbouring Beinn a' Chròin.

The route starts from a layby on the A82 around 4 kilometres south of Crianlarich, following a path to an underpass beneath the railway and a bridge over the River Falloch. A track climbs gently uphill past the grassy flank of Sròn Gharbh for around a kilometre before a boggy path branches right, following a small burn onto easy grassy ground that steepens into a couple of short, rocky sections lower down, with a faint path becoming clearer as the first top of Sròn Gharbh is reached. The route continues over Twistin Hill before the path heads around a rocky knoll and climbs to the summit of An Caisteal, with the tor giving the mountain its name visible nearby — those uncomfortable with the slightly exposed path across it can pass on the right instead.

From the summit, a small path continues south along a clear ridge with a couple of easily negotiated rocky steps down to the Bealach Buidhe, from where most walkers continue to Beinn a' Chròin.

The combined round taking in both Munros from the A82 layby is around 15 kilometres, typically five to seven hours, following the SMC's own recommended route for this pairing from their official Munros guidebook.

The descent from An Caisteal to the bealach is steeper and rockier than it first appears, with route-finding that can be genuinely tricky in poor visibility — this is considered a fine introduction to Munro-bagging for those used to gentler hills, but should still be approached with full navigation skills and equipment.

Parking at the A82 layby is free; Crianlarich is served by both rail and Citylink coach services, around 3 kilometres from the start.