Start from the forestry entrance at R90294 66782 A and walk uphill, taking two lefts and one right off the main track onto a very rough track thats almost blocked near the end with felled trees, to R90538 68028 B. A rough but managable push to the left through the trees and undergrowth will bring you to open bog and the heathery summit cairn. Return the same way.
Another route is from Lisgariff East at R919 692 C.
The summit has views of the distinctive Shannon hill area scenery, smallish hills, forestry, farms and there is a view of Keeper Hill, the local mountain.
The construction of a broad track has made access (as of March 2023) to Cooneen a deal easier. Park at R90294 66782 A and proceed north for about 800m to a crossroads of forest tracks at R90127 67422 D and turn left. About 200m along you will see the broad track of reddish gravel on the right at R89948 67429 E, (presumably constructed for vehicular access) running in a straight line northwards, steepish in parts, but this will take you to within 250m of summit. At the track's highest point, cross the bank on the right to enter the heathery summit area. Watch for a narrow, single file trail as soon as you cross the bank, which makes the remaining trek through heather, sedge grass and reeds a great deal easier. This continues almost to the top, which is an elevated grassy mound, with some stone hints that it might be of megalithic origin. By this route, 35 minutes car to top. Linkback: https://mountainviews.ie/summit/558/comment/5317/