The construction got off to a rocky start; by 1606, Attorney General John Davies observed that the castle foundations had risen ten or twelve feet before being abandoned for two years, leaving them on the verge of collapse. Fortunately, the project was revived, and by 1611 the castle was complete enough for Blayney to move in, though he’d spent a hefty £1,200 of his own money making it habitable alongside the king’s funding.

A map from around 1611-13, now preserved in Trinity College Dublin, reveals what this fortified house looked like in its heyday. The castle was a rectangular structure with substantial corner towers and a small courtyard on its north side, all enclosed within a rectangular bawn (defensive wall) that had bastions at the northwest and southeast corners and a gate to the north. The grounds were quite elaborate for the time, featuring ornamental gardens and fish ponds to the south of the main building, suggesting Blayney intended his new home to be both defensible and comfortable.

The exact location of Blayney’s castle has been something of a puzzle for historians. In 1835, locals pointed to a site on the Diamond opposite Glasslough Street as the castle’s location, though this was more likely just the northern gatehouse of the bawn complex. Despite archaeological excavations in 1996 searching the southwestern area for traces of the castle, no physical evidence has been found, leaving this early 17th-century fortified house as something of a ghost in Monaghan’s historical landscape, known only through old maps and contemporary descriptions.