This tower house, measuring roughly 11.4 metres by 10 metres with walls an impressive 2.3 metres thick, dates back to at least the late medieval period. The structure features a southeast entrance, two double-splayed loops at ground level, and a vaulted second storey; though its upper floors, once accessed by a straight stairway in the southwest wall, have long since crumbled away. Local legend speaks of an ancient Battle of Belgaden fought here between Fiacha Labhrain and Eochy, King of Munster, though the castle itself appears to have taken its name from one of its later occupants.

The castle's documented history begins properly in 1583, when it was held by Eady (or Odo) Lacy, who likely gave the place its distinctive name of Bulgaden Eady. The Lacys maintained their connection to the property into the early 17th century, with Eady Lacy of Bruree receiving a grant for the castle and manor in 1612. By 1641, ownership had passed to Henry Wall of Miltowne in County Cork, an Irish Catholic who possessed what the Civil Survey of 1654;56 described as "an old ruinous Castle". The political upheavals of the period saw the property confiscated around 1652 and granted to Captain Hugh Massy in 1666;67, marking another chapter in the castle's changing fortunes.

Archaeological investigations in 2001 revealed that Bulgaden Castle wasn't merely an isolated tower but part of a more extensive defensive complex. During monitoring work just 11 metres from the castle ruins, archaeologists uncovered a substantial ditch measuring 5 to 6.5 metres wide, aligned northwest to southeast. This defensive feature likely formed part of the castle's original fortifications during its active period from the late medieval era through to the 16th and 17th centuries. The 17th century Down Survey maps depict the tower house castle at Bulgaden Eady, with contemporary terriers noting the presence of "a good Castle and orchard with severall Irish Cabins", painting a picture of a once thriving settlement that has since faded into the Limerick landscape.