The one sitting on a broad hilltop at Galmoylestown in County Westmeath went considerably further. Known locally as Rathmore, this is a trivallate ringfort, meaning it was defended by three concentric earthen banks with two intervening fosses, the broad ditches that separated each ring of defences. Whether that multiplication of effort reflects genuine military anxiety, a demonstration of social status, or simply the wealth of whoever commissioned the work is a question the earthworks themselves cannot fully answer, but the scale of the undertaking is still legible from the hill.

The enclosed area is roughly sub-circular, measuring approximately 47 metres north to south and 50 metres east to west. The inner bank survives best along the south-east and southern arc, but has been reduced almost to a scarp on much of its circuit. The inner fosse is wide and steep. Between it and the next bank lies a wide berm, a flat platform of ground that would have been exposed to anyone trying to cross the ditches, and this berm is broadest on the eastern side. The outermost bank has been largely levelled across the southern and western and northern sections, though its line can still be traced. A narrow entrance gap cuts through all three banks at the east-south-east, with a causeway across each fosse, the widths of the gaps and the causeways varying between roughly two and a half and three and three-quarter metres. The interior rises gently toward the centre. There has been some quarrying along the eastern perimeter, removing a section of the berm and outer bank, and a later field boundary crosses the northern edge of the monument. Aerial photographs taken in 1968 and 1970 captured the concentric rings clearly from above, giving a sense of the full geometry that is harder to read at ground level where the banks have been worn and interrupted by centuries of agricultural use.