Their 1842 map shows a roughly oval enclosure, approximately thirty metres across on its longer north-west to south-east axis and around twenty metres on the shorter south-west to north-east axis. That is about the footprint of a large house. Today, there is nothing to see at ground level whatsoever.

Enclosures of this general type, when they survive, are often the remains of a ringfort or rath, the circular or oval farmstead enclosures that were built in their thousands across Ireland during the early medieval period, roughly between the fifth and twelfth centuries. They were typically defined by an earthen bank and ditch surrounding a domestic area, and they served as the basic unit of rural settlement for much of early Irish society. What made the Walshtown Beg example unusual was not its shape or size, which fall within a fairly ordinary range, but the fact that it was already a cropmark or earthwork feature faint enough to warrant simple mapping rather than detailed description when the surveyors passed through. By the time any subsequent archaeological attention came its way, the surface trace had vanished entirely, leaving only the cartographic ghost on a nineteenth-century map as evidence that something was ever there at all.