Thomas McGinnis.Anne Harper
An American descendant of the Magennis family is astonished to learn he played a key role in the rediscovery of what may be a long-lost castle in Co Down.
Thomas McGinnis, from Philadelphia, has strong ties to the area and frequently stays at the Narrow Water Castle Estate in South Down.
While researching his family history, he struck up a friendship with local historian Anne Harper. Years later, that connection has led to the exciting rediscovery of a previously unmapped Historic Monument.
Located on forestry land within the Narrow Water Estate, the structure had never before been formally identified. Historic newspaper reports refer to the building as an “Old Castle”, but in recent decades it has been known locally as a “folly."
Archaeological surveys carried out during the 20th century failed to recognise its potential significance.
The rediscovered structure on forestry land within the former Narrow Water Estate.
“I am thrilled," Thomas said about the discovery.
"Anne and I have spent many years carrying out fieldwork in the area and helping each other with our research, but this discovery was completely unexpected.
"I took her to see the folly near where I was staying, but the moment she saw it, her jaw dropped. She said, ‘That’s not just a folly!’ It looks like she was right.
"The thought that this building could be the remains of an important site, possibly even linked to my family, is incredibly exciting.”
Thomas McGinnis and Anne Harper at the newly-identified monument, March 2026.
Anne said: “When people think of Narrow Water Castle, they usually think of the beautiful tower house by the river, or the 19th-century building on the estate built by the Hall family. While the tower house is associated with the Magennis Lords of Iveagh, records show it was originally built by the English.
“The Magennis family did build fortifications in South Down, for example, at Rathfriland, but so did the Normans, and some of their buildings were later repurposed by the Magennis.
“Strategically, this would have been an ideal location for a castle. The structure has clearly been altered several times over the centuries, probably as fortunes changed, but I believe there is little doubt that parts of this building predate both of the other known Narrow Water castles.”
This isn’t the first time that built heritage has been located after being omitted from Ordnance Survey maps and Archaeological surveys of the area. Nearby Bagenal’s Castle in Newry was ‘rediscovered’ inside a bakery in 1996 despite a widespread belief that it had been lost to history.
The Historic Environment Division of the Department for Communities has confirmed that the site at Narrow Water will now be listed as a Historic Monument, with further research to follow.
“This building has the potential to significantly enhance our understanding of South Down’s heritage," Anne added.
"It is wonderful to have added to the archaeological record, and particularly fitting that a descendant of the Magennis has played such an important role in shining this light onto our heritage.”
*You can learn more about historian Anne Harper on her website, Facebook, Instagram, and TikTok pages.