Though no stones remain visible above ground today, this site once hosted a medieval castle that guarded the strategic crossing point over the River Barrow. The castle appears on both the 1841 and 1909 Ordnance Survey maps, testament to its lingering presence in local memory long after its physical structures had vanished.

The castle formed part of a broader medieval landscape in Tankardstown Parish, which included at least two defensive structures positioned to control river access. According to O’Hanlon and O’Leary’s 1907 History of the Queen’s County, this northern castle stood alongside a church, now reduced to ruins within a graveyard, and several abandoned houses; all features that Sir William Petty had documented in his earlier maps. Just a quarter mile to the south, traces of another castle could still be discerned in the early 20th century, suggesting this was once a heavily fortified stretch of the Barrow valley.

Today, visitors to Tankardstown will find the ruined church and its surrounding graveyard still marking the landscape, along with St. Thomas’ Well nearby. While the castle sites themselves have been reclaimed by time and agriculture, their locations remain mapped and catalogued in the Archaeological Inventory of County Laois, serving as invisible monuments to the medieval communities who once controlled this vital river crossing on the western banks of the Barrow.