Yet a single line in Maurice Craig's 1969 architectural survey of Dublin records something now entirely vanished: houses of the Dutch-Billy type that formerly stood on Mountpelier Hill, their gabled fronts long since gone from the landscape without leaving an obvious trace in the historical record.

The Dutch-Billy was a distinctive house form that became fashionable in Dublin during the late seventeenth and early eighteenth centuries, most likely arriving with the architectural influences that followed the Williamite period. The style is characterised by a tall, curved or pointed gable facing the street, a form common in the Low Countries and northern Europe but relatively unusual in an Irish context. In Dublin, Dutch-Billy houses were once widespread, particularly in the older parts of the city, though the vast majority were demolished or altered beyond recognition over the following centuries. Craig's passing reference to examples on Mountpelier Hill is notable precisely because it places this urban house type in a semi-rural, elevated setting outside the city centre proper, suggesting a more dispersed presence than surviving examples might indicate. Beyond Craig's brief mention, the historical record for these particular buildings appears to be thin.

Because the structures themselves no longer survive, there is nothing physical to seek out at the site today. Mountpelier Hill is nonetheless accessible as part of the Dublin Mountains, reached via Killakee Road, and the walk to the summit takes in open heathland with wide views back towards the city. Anyone with an interest in the vanished built environment might find a certain quiet interest in looking at the hillside with Craig's note in mind, aware that the landscape once included gabled houses whose exact appearance, dates, and occupants have not been recovered. The Hellfire Club ruin at the top remains the hill's most tangible historical feature, but the lost Dutch-Billies are a small reminder of how much ordinary architectural history goes unrecorded.