15/05/2026
Porterstown Castle & The Bishop's Arch
The late David Hughes told me about an ornate archway, leading to a courtyard, that used to be on the Porterstown Road. He called its demolition, in the 1960s (?), an act of cultural vandalism. David called it "The Bishop's Arch", possibly as it was north of Annfield (home of Archbishop John Troy),
However, it transpires that this archway may have been the entrance to Porterstown Castle (now the site of the Canal Banks development). So what do we know about it?
We know that the townland of Porterstown most likely dates from the Anglo Norman invasion (1200s) and was named for the Porter family. We know Richard Porter died in 1472, leaving a considerable fortune. We know that the lands transferred to the FitzLyons family, also in the 1400s.
In the 1500s, the land transferred to the Finglas family, through the marriage of Alson FitzLyons and Roger Finglas. She had previously been married to Edward, Lord Howth. Alson's 2nd husband was very prominent, in the military campaigns of both Queen Mary and Queen Elizabeth.
In 1641, Porterstown was owned by an Edward Dowde. The Civil Survey, drawn up during Cromwell's time, described Porterstown as "100 acres: 80 Arable, 14 Pastur and 6 Mead." The survey also states that there was one small castle, 2 or 3 cottages, an orchard and garden; and some Ash trees. During Cromwell's time, Porterstown was occupied by Colonel Richard Lawrence, of Chapelizod.
With the Restoration of Charles II, to the throne (1660), ownership changed again. Porterstown Castle was occupied by Roger Boyle, 1st Earl of Orrery and was considered the most important dwelling in Castleknock.
Towards the end of the 1700s (around the time the canal was being built) "an arched gateway beckoned the former importance of the place, but even then all other trace of the dwelling occupied by Lord Orrery had disappeared".
We know that Porterstown House, on the opposite side of the road was a later structure, but this arched gateway, associated with Porterstown Castle, existed til relatively recently.
Can anyone remember what the arch looked like?
Sources: FE Ball's History of Dublin, referencing Austin Cooper's Dublin.
The Civil Survey by Robert C Simington
Map; TCD digital collection.
Image: Soar satelite (1966)
Fingal Heritage