The North Cork Archaeological Inventory gives the following description.
Cupmarked standing stone: Not shown on 1842 and 1904 OS maps. In level pasture, overlooking Blackwater valley to W. Stone (H 1.63m: 1.48m x 0.87m) is subrectangular in plan, long axis N-S. About 15 cupmarks on W face (average diam. 0.07mm)
The standing stone is just to the rear of a farm-building. Best to mark in the village of Knocknagree (Cnoc na Graí) (Hill of the Sun?) and walk down. It can be spotted over the ditch after an old lane just past the farm-house.
Cup-marks aren't that deep really and if I hadn't read they were there would not have noticed them as being such.