The difference in vegetation growth above a buried fosse, a defensive or boundary ditch dug into the ground, is just sufficient to register from above, producing a faint but legible mark that aerial and satellite imagery has captured across different decades.

The enclosure is roughly D-shaped or subrectangular, measuring approximately 30 metres on its northeast to southwest axis and about 27 metres northwest to southeast. It sits towards the bottom of a north-facing slope, a positioning that would have offered some natural shelter. The feature was first reported by Jean Charles Caillére, and it appears in mapping imagery from as early as 1999 to 2003, remaining visible in more recent aerial coverage from 2022. The fact that the mark has persisted across more than two decades of imagery suggests a reasonably well-preserved fosse below the surface, even if nothing dramatic announces itself at ground level. Enclosures of broadly this form and scale are found widely across Ireland and often relate to early medieval settlement, though without excavation the date and function of the Growtown example remain open questions.