The plan for improving the harbour was projected in 1814, and the expense of carrying it into effect was estimated by the late Mr. Nimmo under whose superintendence it was conducted, at £19,385; but from the necessary additions and subsequent improvements, that sum had, in 1821, amounted to £42,500, and in 1832 to £93,236; and it was then found that £15,000 more would be requisite to complete this important work, making a total expenditure of £108,286. The pier, which extends in a north-eastern direction for more than 700 feet, is defended by a breakwater, stretching from Dunmore Head more than 800 feet into the water, varying from four to six fathoms in depth, and presenting towards the sea an inclined plane paved with massive blocks of stone, which breaks the force of the waves before they reach the parapet of the pier, which has an elevation of 70 feet.
The pier and quay are built of a silicious stone quarried in the neighbouring hills, and faced with a fine granite, which after the exhaustion of these quarries, was brought from the county of Carlow. The basin comprises an area of six acres, and is sheltered by the Mole and Dunmore hill from the west and south-west winds, on the north-east by the promontory of Craden Head and on the east by the peninsula of Hook; the depth at the entrance is 15 feet, and at the innermost part 8 feet at the lowest ebb.
At the pier head is a lighthouse, displaying a red light towards the sea, and a bright light up the harbour, which is easily accessible, but it is gradually filling with sand, whence it is in contemplation to remove the mail packet station to the quay of Waterford, thus enabling the post-office to place a superior class of steamers on the line. This is now the station of the mail packets between England and the South of Ireland, and one of four ports for British correspondence. There are four steamers, each of 80-horse power, on this station; the packet with the mail for Milford leaves Dunmore daily at ½ past 6 o'clock in the morning, and on the arrival of the packet from Milford, a coach conveys the mail and passengers from Waterford: the distance between the two ports is 80 miles.
The fishery is still carried on here, in which three hookers of from 14 to 18 ton's burden are employed in the cod and ling fishery in the deep sea, and 30 yawls in the herring and in-shore fishery. Dunmore is also the pilot station for vessels making for Waterford Harbour. The limits of the harbour by the 58th of Geo III., cap. 72, extend from Shannon Point to Ardnamult Point; the duties of the Commissioners of this harbour have been annexed to the Board of Public Works. In the rocks in the bay of Dunmore is a fissure of no great extent, called the Cathedral, and to the west of it, near the promontory of Red Head, is another, called the Bishop's cave, 100 feet in length and 24 feet wide.