A subcircular rath roughly fifty metres across from north to south, it has been reduced over centuries to a degraded scarp, a partial fosse, and a remnant outer bank. The fosse, a defensive ditch typically dug around such enclosures, and its accompanying outer bank survive only along a southern arc, from the south-east around through the south to the west-south-west. Everywhere else, the ground offers no visible trace that anything was ever here.

A rath is an early medieval farmstead enclosure, usually defined by one or more earthen banks and ditches, and built to protect a household, its livestock, and its stores. Thousands once existed across Ireland; most have been degraded by centuries of agriculture, land clearance, and simple time. The Tonlegee example sits some thirty metres south-east of a second ringfort, suggesting that this was once a settled, inhabited landscape rather than an isolated site. Particularly intriguing is what the archaeology records as a possible internal division running roughly west-north-west to east-south-east through the interior, a feature that might indicate the rath was subdivided for different uses, though the evidence is faint. The site was documented in the Archaeological Inventory of County Galway, Volume II, covering North Galway, compiled by Olive Alcock, Kathy de hÓra, and Paul Gosling and published in 1999.