What was once recorded as a roughly quadrangular enclosure, around 60 metres by 50 metres and planted with trees, now survives only as a low earthen bank curving from the north-west through north to the north-east, largely obscured by whatever tree cover remains. The enclosure itself has left no trace on the ground that can be readily made out.

The 1929 third edition of the Ordnance Survey six-inch map recorded a slightly curving field boundary running along the northern edge of this tree-planted enclosure, suggesting the feature was still legible to surveyors at that time. Enclosures of this general type, earthen banks defining a bounded area in the landscape, appear throughout Ireland in many different periods and contexts, from early medieval settlement enclosures to later post-medieval garden or demesne features. At Knockogonnell, the notes compiled by Olive Alcock, Kathy de hÓra and Paul Gosling for the Archaeological Inventory of County Galway do not assign the site a firm date or function, which leaves its origin genuinely open. The curving northern bank is the only physical remnant of whatever was once enclosed here, and the map evidence is now the more reliable record of the site's former extent.