The castle appears on the 1654-56 Down Survey map of Coshlea Barony as a tower house, one of many fortified residences that once dotted the Irish landscape. By 1640, the structure was already described as ‘an old ruynous Castle’ belonging to Meiler Fitz Harrys, an Irish Catholic landowner who also possessed a grist mill and tucking mill seat on the property. The various spellings of the townland’s name, from Shaneboye in 1590 to Ballyshondeby in 1655, reflect the fluid nature of place names in early modern Ireland, with some confusion even arising between this site and nearby Ballyshanedehey.

The castle’s decline was gradual but thorough. When antiquarian Thomas Johnson Westropp surveyed the area in the early 1900s, he noted that only a single arch had survived into the 1840s, as recorded by the Ordnance Survey. The Survey team found that ‘there stood a Castle formerly, part of an arch belonging to which yet remains’, but even this last architectural fragment has since vanished. The Down Survey terrier for the parish map of Kilcoane and Effin simply noted ‘the Ruines of a Castle’ on the lands of Miles Fitz Harrish, offering a glimpse into the property’s state during the Commonwealth period.

Today, no surface remains are visible at the site; the castle has been completely levelled, leaving only its documentary traces in historical records. The transformation from fortified residence to agricultural land reflects broader patterns in Irish history, where tower houses that once served as symbols of local power gradually gave way to changing political and economic circumstances. The site remains significant as part of Limerick’s medieval heritage, even if its stones have long since been repurposed or lost to time.