Knocknapeasta lies high above the Hag's Glen to the N and the Black Valley to the S. It's conical, rocky summit is the end point of the most challenging ridge walk in the country. However, access from other directions is easier. Great views esp. of the Big Gun, Carrauntoohil, Purple and indeed much of Corca Dhuibhne and Beara can be visible.

N. Park at Cronin's Yard V83608 87337 A or Lisleibane V82707 87311 B and follow the obvious track towards Hag's Glen. You've a few choices from here :
a) to avoid the challenge of the arête head into the glen as far as approx. V82303 85034 C and from here head SE up The Bone. The route is fairly obvious and as you ascend it becomes narrower and the track more obvious. If taking this route down be very careful to keep right at around V83100 83899 D.
b) leave the track at approx. V83047 86583 E and head for Loch Cummeenapeasta. If you care to take on The Big Gun go E at the lake and head steeply up a huge boulder field [rock hopping is easier than finding a way around] to the summit of Cruach Mór. See comments on CM and TBG for more details. 3 to 4 hours.

If you'd prefer to avoid the arête go to the right side of the lake and ascend the equally steep NW spur of K. 2.5hrs +

SE Park with care near V85642 82670 F E and strike out NW up a long, well-defined spur to Feabrahy. Expect steeper ground thereafter - a slog will take you to the col to the SW of the summit. Allow 2hrs+

Notable tracks incl. track/4190. track/3529 and track/3790. Linkback: https://mountainviews.ie/summit/4/comment/4764/

I set off from the Black Valley hostel but, after a grim start on rough land with bracken higher than myself in places, I reached an insurmountable fence and had to return to the road. Although feeling more like the Australian Outback then the wilds of Kerry in temperatures over 30 degrees C, I followed the Black Valley road as far as Shamrock Farmhouse B&B, where I got permission to go through fields en route to Lough Googh.

A pleasant walk on short grass took me through several gates then good easy ground (but without a path) led to an easily-negotiated area of broken slabs and outcrops above 400m. I stopped for a break at Lough Googh, overlooked by beetling crags to the west. From there, easy grass flanks took me upwards (to the south-west), with a short path on the steepest section. Once on the ridge connecting Feabrahy and Cnoc na Péiste (at 600m), I continued north-west on fairly steep slopes with scattered rocks. Above 850m, I slanted leftwards, steeply uphill, to reach the col between Maolán Buí and Cnoc na Péiste, then a good path took me along the broad easy-angled ridge to the summit - 24 degrees C in the shade and nobody in sight. Views were a little hazy but the intimidating-looking ridge to An Gunna Mór looked sharp enough!

I returned to the hostel the same way although, with more time and less heat, a circular route over An Gunna Mór, Cruach Mhór and descending by the Derrycarna River would make a fine walk. Linkback: https://mountainviews.ie/summit/4/comment/15167/

The exciting knife-edge from Cnoc na Peiste to Cruach Mhor Linkback: https://mountainviews.ie/summit/4/comment/2313/

Cnoc na Péiste from the shore of the lake. Blue arrow indicates the location of a blue rope which is tied to the wing in the water (and to a rock on the other end). No use pulling it: the wing is too heavy. The red arrow shows the location of a memorial plate. The plane crashed into the mountain 500 feet above this plate. Linkback: https://mountainviews.ie/summit/4/comment/1904/

Cnoc na Péiste from the ridge after The Big Gun. The path after the col under the Big Gun starts on the south side then crosses over to the north side then back to the south side - the only hair raising bit is on the north side - a two foot ledge in places with nothing between you and Lough Cummeenapeasta except fresh air. Linkback: https://mountainviews.ie/summit/4/comment/1145/