From the Nire Valley car park (S27684 12842 A), room for 20 cars but note this fills up fast on weekends, walk back down the road towards Ballymacarbery for about 500 meters. You'll come to a gate on your left with a muddy track leading down the slope towards the river.
Cross the river over a makeshift bridge and follow the rising track towards the mountains.
After passing a ruined farmhouse the track leads through a galvanised gate and out across the bog.
The track goes much further than shown on the map and although in places it is indistinct, you can follow it all the way to approximately S28313 11290 B with little difficulty.
As the track ends pick your way upwards over heather to the top of the waterfall (S300 112 C)
Cross white gravel and peat hags to the featureless summit. Linkback: https://mountainviews.ie/summit/81/comment/4841/