The stone at Corrower is not simply a standing stone, and not simply an ogham monument; it appears to be both, one use grafted onto the other at some unknown remove of time. It leans gently eastward, its stepped top rising to a flat-peaked northern end, and cattle have been rubbing themselves against its narrow edges long enough to polish parts of the surface smooth.

Ogham is an early medieval Irish script, typically carved as a series of notches and scores along the edge or edges of a stone, and it is found here on both the northern and southern ends of the slab. The scholar R. A. S. Macalister, writing in 1945, argued that the exceptional size of the stone pointed to a much older origin: a prehistoric standing stone that a later ogham carver chose to appropriate rather than raise a new monument from scratch. The partial inscription he recorded reads, in transliteration, as something like: --]MAQ CERAN[I] AVI ATHECETAIMIN, a formula characteristic of early medieval memorial stones, naming a person in relation to their father and grandfather or kin group. The scores are described as broad and shallow, pocked and worn. On the northern end, lichen has obscured the upper half of the inscription almost entirely, and faint possible notches visible between 0.8 and 1 metre above the ground may be all that remains legible there. The southern end fares better; its inscription runs clearly from the top of the stone down to about 1.3 metres above ground, where the edge broadens and flattens and the carving stops. The stone sits on a low rise, with the Ox Mountains defining the eastern horizon and Nephin rising on the south-western skyline. A cairn crowns a hill roughly 65 metres to the south, and a rath, the earthen remains of an early medieval enclosed farmstead, sits on a low hill about 380 metres to the north-north-east. The Corrower stone did not stand alone in the landscape then, and it does not stand alone in it now.