Northburgh Castle, Medieval castle ruins in Greencastle, Ireland

Northburgh Castle is a medieval castle ruin in Greencastle built on a rocky platform overlooking the mouth of Lough Foyle. The structure includes an oval courtyard with twin polygonal towers at the gatehouse that once controlled water access.

Richard de Burgo, Earl of Ulster, built the castle in 1305 to control Lough Foyle and monitor the O'Neill and O'Donnell clans. This fortification became a key tool in Norman efforts to hold power in the region during the late Middle Ages.

The gatehouse shows how medieval builders mixed military defense with administrative power in a single structure. Walking through the ruins, you can see how this design worked both as a fortress and a seat of authority.

The ruins are accessible from two entry points: one from Greencastle town center and another from the nearby shoreline. Access is open to the public and you can explore at your own pace on relatively flat ground throughout the site.

Walter Liath de Burgh was imprisoned in 1331 by his cousin William Donn de Burgh, the Brown Earl, and died of starvation in February 1332. A skeleton in Derry City's coat of arms is said to commemorate this. William's sister was later found dead beneath the battlements.