A ringfort, or rath, is an early medieval enclosure, typically a circular earthen bank surrounding a farmstead or dwelling, and thousands of them survive across Ireland in varying states of preservation. The one recorded at Tonaknock in north County Kerry is not among the survivors. What exists instead is a paper trail, a site that can be followed across historical maps but no longer found in the ground.

The fort first appears on the Ordnance Survey map of 1841 to 1842, recorded as a circular enclosure in the Kerry landscape. By the time the later OS edition was produced in 1916, something else had been noted: a cave marked within the interior. This detail is quietly intriguing. Ringforts were sometimes associated with souterrains, underground stone-lined passages used for storage or refuge, and it is possible that what the 1916 surveyors recorded as a cave was a surviving feature of that kind, visible even after the earthwork banks themselves had been reduced. The northern to eastern sectors of the enclosure appear to have been levelled by that point, and today no surface trace survives at all. The fort has been absorbed entirely into whatever agricultural or land-use changes overtook it in the intervening generations.