In about 1640, Lord Power of Curraghmore, who owned a large amount of property in the area, built a castle on the cliff overlooking the strand about two hundred metres from St. Andrew's Church.   The castle must have been a beautiful sight, but by the middle of the next century it was falling into ruin and now just one tower remains.

In 1824 R.H. Ryland, in his history of the county and city of Waterford, describes Dunmore East as follows:

"Nearby at the entrance of (Waterford) Harbour is the village of Dunmore, formally a place of resort for fishermen, but now a delightful and fashionable watering place.   The village is situated in a valley, with a gentle slope towards the sea; the houses are built irregularly, without regard to site or uniformity of appearance, except that they all look at the same point  -  the Hook Lighthouse, on the opposite coast.   Most of the cottages are built of clay and are thatched with straw, and generally let during the summer season from one to three guineas a week.   On the hill, which forms the background of the picture, are the ruins of a church"

Nearly two hundred years later the thatched cottages are still there, though the rents have increased somewhat!   The ruined church refers to the old church of Killea (Cill Aodha  -  Aodh's Church) thought to have been built in the twelfth century, one wall of which still stands, opposite the Catholic church of The Holy Cross, at the top of Killea hill.

In 1814, however, dramatic changes took place when Alexander Nimmo, the Scottish engineer (builder of Limerick's Sarsfield Bridge) commenced work on the new Harbour at Dunmore to accommodate the packet station for ships, which carried the Royal Mail between England and Ireland.   The work consisted mainly of a massive pier or quay with an elegant lighthouse at the end.  Nimmo's original estimate had been £20,000 but at the time of his death in 1832 £93,000 had been spent and the final cost was £108,000.   By then (1837) the Harbour had started to silt up, and the arrival of steam meant that the winding river could be negotiated easily, so the packet station was transferred to Waterford.

However the existence of what for that time was a great sheltered Harbour meant that Dunmore East was to gradually become an important fishing port.   The Harbour is one of the five designated National Fishery Harbours, and has the second highest figure for fish landings after Killybegs.   Dunmore has some notable marine firsts to its credit, with the first Irish woman to qualify for a skipper's ticket in fishing; the first official woman crew member in an RNLI Lifeboat, and the world record holder for the largest tuna caught on a rod.