How difficult is An Caisteal?

An Caisteal carries a 4/5 (challenging) grade on the OutdoorSCOT scale. Count on about 17km, 876m of ascent and a 5-8 hour day on the standard route. Ground conditions: The Derrydarroch path through the railway underpass is firm but boggy in places.

How much drop does An Caisteal have?

The drop is 474m: measured from the summit of An Caisteal down to the saddle joining it to higher terrain.

Where's the parking for An Caisteal?

Park at NN369239. Double-check the grid reference on an OS map first; informal laybys here fill early in high season.

What's the best month to climb An Caisteal?

Aim for May, June, July, August, September, October on An Caisteal. In the remaining months treat it as a winter hill — full kit, solid navigation, and a look at the relevant SAIS avalanche forecast before you go.

Can dogs go up An Caisteal?

Dogs are fine on a lead. The route passes livestock or ground-nesting bird habitat, so keep them close throughout.

By Gary

Photo: Steven Brown / CC BY-SA 2.0 via Geograph

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Munro · Arrochar & Trossachs

An Caisteal

An Caisteal (995m) — "the castle" — is one of the Crianlarich Munros, the cluster of summits that wall in the south side of Strath Fillan above the A82. The hill takes its name from the prominent rocky summit cone that resembles a small castle when seen from the south. Almost always climbed in tandem with its eastern neighbour Beinn a' Chroin on a fine short Southern Highlands round.

Gaelic: “the, castle” · Pronunciation: an kash-til

Quick facts

Height: 995.9m/ 3267ft
Prominence: 474 m
Distance: ~17 km
Ascent: ~876 m
Time: 5–8 hrs
Difficulty: 4 / 5Serious
Grid ref: NN378193
Parking: NN369239
Nearest city: Stirling· 49km
Dogs: Dogs on lead required near livestockDog-friendly guide ↗

Height and prominence cross-checked against the Database of British and Irish Hills (CC BY).

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Standard route

Farm track / path 25% · Steep hillside 40% · Summit ridge 35%

17km · 876m ascent · 4.9 hrs

Park at the small Derrydarroch lay-by on the A82, around 4km south of Crianlarich. Cross the West Highland Line via the underpass, then follow the path south up Coire Ardrain to a high bealach. Climb the rocky north ridge of An Caisteal directly to the summit. From the summit, descend the east ridge to Beinn a' Chroin, traverse its long summit ridge, then descend north back to the A82. Around 14km with 1100m of ascent for the pair.

Terrain

The Derrydarroch path through the railway underpass is firm but boggy in places. Above the woods the going turns to rough heathery hillside with broken mica-schist outcrops. The north ridge of An Caisteal is rocky with one or two short scrambly steps near the summit. The summit cone gives the hill its castle-like name. The connecting ridge to Beinn a' Chroin is broad mossy turf with some rocky outcrops. The Beinn a' Chroin summit area has a confusing three-topped layout.

In winter

A genuine mid-grade winter day for Southern Highlands standards. Under snow An Caisteal's summit cone becomes a Grade I winter scramble. Both summits build persistent cornicing on their northern flanks through the season. The A82 itself remains reliably gritted and Crianlarich works well as a winter base.

Outside the SAIS network. No Scottish Avalanche Information Service forecast covers An Caisteal. SAIS forecasts six areas only — Northern and Southern Cairngorms, Creag Meagaidh, Lochaber, Glencoe and Torridon — and this hill is outside all of them, so there is no avalanche forecast to read for it. In winter, use MWIS West Highlands ↗ for mountain weather, judge snow stability from first principles, and treat any cornice or wind-loaded slope with extra caution.

Best time of year

Best OK Avoid

Getting there

Glasgow1h 23m
Edinburgh2h 6m

Parking: NN369239

OS maps: OS Landranger 50, OS Landranger 56

Mobile signal: Intermittent signal at the Derrydarroch car park on the A82. Signal is absent above 700m. Download mapping before departing Crianlarich.

Current conditions

Daylight Today

14h 45mwalking daylight

Sunrise: 06:33
Sunset: 20:00
Civil dawn: 05:54
Civil dusk: 20:39

NOAA Solar Calculator · 7 September 2026

Pair with

Curated multi-hill combinations from An Caisteal.

Two-hill day
An Caisteal + Beinn a' Chroin
An Caisteal and Beinn a' Chroin from Derrydarroch — the Falloch two-Munro day.
24km · 1100m ascent · 6 hrs

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Around An Caisteal on the SCOT network

Getting there, basing yourself, and what to do off the hill.

On TripSCOT

town

Base yourself in Luss

West Loch Lomond village — Highland Boundary, Loch Lomond Way

26km from the hill

tripscot.co.uk

Before you go

Hillwalking carries real risk and the responsibility for any day on the hill is yours. Conditions in Scotland change fast and can differ sharply from the forecast — check the weather and the ground before you commit, turn back when the day stops working, and carry map and compass with the ability to use them rather than relying on a phone.

The distance, ascent and time shown on this page are editorial estimates for the usual line, not measurements from a recorded track — that is what the ~ means. Treat them as a rough shape of the day. Your own pace, the conditions and the exact line you take will all move them.

Mountain forecasts: MWIS and the Met Office mountain forecast. Access rights and responsibilities are set out in the Scottish Outdoor Access Code.

We check what we publish, but we cannot check the route on the day you walk it. Nothing here is a substitute for your own judgement.

An Caisteal — common questions

How difficult is An Caisteal?: An Caisteal carries a 4/5 (challenging) grade on the OutdoorSCOT scale. Count on about 17km, 876m of ascent and a 5-8 hour day on the standard route. Ground conditions: The Derrydarroch path through the railway underpass is firm but boggy in places.
How much drop does An Caisteal have?: The drop is 474m: measured from the summit of An Caisteal down to the saddle joining it to higher terrain.
Where's the parking for An Caisteal?: Park at NN369239. Double-check the grid reference on an OS map first; informal laybys here fill early in high season.
What's the best month to climb An Caisteal?: Aim for May, June, July, August, September, October on An Caisteal. In the remaining months treat it as a winter hill — full kit, solid navigation, and a look at the relevant SAIS avalanche forecast before you go.
Can dogs go up An Caisteal?: Dogs are fine on a lead. The route passes livestock or ground-nesting bird habitat, so keep them close throughout.
Will I get phone signal on An Caisteal?: Intermittent signal at the Derrydarroch car park on the A82. Signal is absent above 700m. Download mapping before departing Crianlarich.
Is An Caisteal safe in winter?: A genuine mid-grade winter day for Southern Highlands standards. Under snow An Caisteal's summit cone becomes a Grade I winter scramble. Both summits build persistent cornicing on their northern flanks through the season. The A82 itself remains reliably gritted and Crianlarich works well as a winter base.

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