This large enclosure, measuring approximately 120 metres from east to west and 60 metres from north to south, sits near the boundary with the neighbouring townland of Drombeg. Despite its considerable size, the site never appeared on any of the historic Ordnance Survey maps, only coming to light through aerial surveys conducted between 2005 and 2020.

The monument appears to consist of two connected enclosures that likely functioned as a single complex. The main rectangular earthwork is accompanied by a smaller annexe on its north-northeastern side, measuring roughly 31 by 39 metres. This secondary enclosure sits between the larger structure and the townland boundary, suggesting the entire monument was deliberately positioned at this territorial edge. An old field boundary, recorded on the 1840 Ordnance Survey map, cuts through the western quarter of the main enclosure, indicating that local farmers had long since reclaimed parts of the site for agricultural use.

The location places this earthwork within an interesting archaeological landscape. A ringfort lies just 200 metres to the northeast, whilst Castle Ievers stands 550 metres to the south-southwest, suggesting this area held strategic or social importance over multiple periods. The rectangular shape and ditched construction of the Tullerboy enclosures point to a possible moated site, a type of medieval settlement typically associated with Anglo-Norman colonisation, though without excavation its exact date and function remain uncertain.