The rock carries two carved motifs: a cup with one ring encircling it, and a cup with two rings. These are classic examples of prehistoric cup-and-ring marks, a form of rock art found across Atlantic Europe and the British Isles, in which circular depressions, the cups, are surrounded by one or more concentric carved channels. Their purpose remains genuinely unknown, though theories range from territorial markers to ritual or astronomical significance.

The site was identified as rock art by George Currie in 2018, making it a relatively recent addition to the documented record of Kerry's prehistoric landscape. It lies roughly twenty metres to the south-east of a previously recorded monument in the same area. Kerry has yielded a number of rock art sites, particularly in the south-west of the county, where the tradition of incising these abstract forms into exposed stone surfaces appears to have been well established during the Bronze Age. The simplicity of the marks at Ballynakilly belies the considerable effort involved in their making, worked into the stone surface with another hard stone, likely over a sustained period.