What survives is enough to read the original ambition of the place, even if centuries of farming have done their best to erase it.

This is a rath, the Irish term for a ringfort, a type of enclosed farmstead typically dating from the early medieval period, roughly 500 to 1000 AD, though many remained in use or were adapted long after. The enclosing bank at Sionhill has a diameter of approximately 49 metres and was accompanied by an external fosse, a defensive ditch dug around the outside of the bank. By the time anyone formally recorded the monument in 1970, the bank had been reduced in most places to a low scarp, a kind of slumped earthen slope, with several gaps in its circuit. The fosse, wide and shallow, remained visible around much of the northern and eastern arc. The best-preserved stretch of the bank runs from east to south-east. A later trench, unrelated to the original construction, was dug along the south-western exterior at some point, adding to the confusion of the ground surface. A large shallow quarry hole also marks the exterior on the south-east to south-south-east side. Inside, the ground slopes gently toward the north-east, and faint traces of cultivation ridges running north-east to south-west suggest the interior was farmed at some stage, a pattern confirmed by more recent aerial photography showing the whole interior ploughed across. The original entrance has not been clearly identified, though a possible gap exists at the east-south-east, where the bank dips and a depression sits at its base. Sionhill House stands about 170 metres to the north-west, and the ridge position that once made the site strategically useful still gives good views east and west across the Westmeath landscape.