Carrauntoohil (O'Shea's Gully) + The Big Gun traverse

Carrauntoohil is Ireland's highest point. Most hikers approach the mountain from the east, parking at either Cronin's Yard or Lisleibane, though ascents from the west are also popular here on Hikr.

The three most popular routes from the east are:

• O'Shea's Gully, which aims for the saddle north of the main summit.
• Devil's Ladder, which reaches the saddle between Carrauntoohil an Cnoc na Toinne through an eroded gully.
• The zigzags, technically the easiest route, though relatively unpopular since it climbs Cnoc na Toinne, involving an additional ascent of 100m each way.

I choose O'Shea's gully (T3, I) for my ascent, since it seems the most interesting route, as well as allowing me to traverse Carrauntoohil on the way to my second goal of the day: the ridge towards Cruach Mhor. From Cronin's yard, I follow the main track towards Carrauntoohil, going across two bridges and one gate. Just before a ford, I turn right (staying north of the river) onto a less distinct path. By the time you are above the lake of Lough Gouragh, you should have found a well-trodden path again around the 370m contour. The trail climbs (with a few bits of easy scrambling) to the grassy floor of a small cirque at 520m, before climbing along the edge of the cirque to a next level around 640m. A nice short scramble up a gully leads to a tarn at 700m. The remainder of the ascent is less interesting, as the path climbs 200m over scree-covered terrain to the saddle north of Carrauntoohil.

Wanting to avoid the hustle and bustle on the Carrauntoohil summit, I have my lunch break on the minor top of The Bones Peak (959m) on the ridge between Carrauntoohil and Beenkeragh. A pleasant short scramble leads here, and the views are arguably more spectacular on The Bones Peak than on Carrauntoohil itself. Afterwards, I scramble back down to the saddle and hike up to the Carrauntoohil summit. There's a large cross here and some wind shelters. Even though it's a Tuesday, there are about 30 people here enjoying the perfect weather.

I don't hang around for long and head over to Croc na Toinne. After the routes of the Devil's Ladder and the zigzags have branched off, it's all quiet again on the hills. There's a 200m ascent onto Cnoc an Chuillinn, afterwards the ridge continues without difficulties and without a significant change in altitude until the highest point at Cnoc na Peiste.

The ridge gets a lot more challenging (T4/I obligatory; T5/II optional) in between Cnoc na Peiste and Cruach Mhor, with the summit of The Big Gun in the middle. The easier option is to follow bits of a path (mostly in the south face between Cnoc na Peiste and the Big Gun, and mostly in the west face between the Big Gun and Cruach Mhor) that avoids most difficulties. Myself, I try to stay on the ridge as much as possible, which offers lots of interesting scrambling. The descent on the north ridge of the Big Gun offers a particularly exhilarating line of sustained scrambling. There is one crag in the middle between the Big Gun and Cruach Mhor that I don't manage to traverse, instead finding a way around on the west side. Otherwise I stay directly on the ridge all the way. It's a great route, but do take into account that the scrambling does take its time. It took me about 1h15 to reach the large shrine ("grotto") with Madonna-statue on Cruach Mhor from Cnoc na Peiste, though the ridge connecting both summits is just 1km long.

Descending Cruach Mhor on the east ridge, the terrain is still rough, but without sustained scrambling. Soon, I say goodbye to the ridge and I descend along a fence in a direct line towards Cronin's Yard (best to stay west of the fence to avoid copious heather). There are a couple of larger fences to be climbed nearer to Cronin's Yard if you want to avoid a detour.

I find it surprising that this is the first Hikr ascent of the ridge between Carrauntoohil and Cruach Mhor, because this is undoubtedly one of the greatest mountain routes in Ireland!

Many variations are possible:

• For longer options, consider starting with Beenkeragh (possibly via a climb or scramble on the Stumpa / Hag's Tooth) or extending the route to the east with Cnoc na Bhraca.
• If a linear hike is a possibility, then a full MacGillyCuddy's Reeks traverse from Cruach Mhor to Caher would be very appealing.
• For a shorter variation, excluding Carrauntoohil and instead taking the Maolan Bui north-west ridge ("The Bone") would make a very appealing route that almost completely avoids the Carrauntoohil mass tourism.