When Benjamin Fisher surveyed the island in 1804 with a view to building a Martello tower
and battery as part of plans to construct a ‘chain’ of coastal defences from Balbriggan to Bray. The Martello tower and associated gun battery were constructed.
In 1804-5, and the ownership of the island passed from the archbishop of Dublin to the Board of Ordnance who maintained the island as a military base throughout the nineteenth century, though cattle grazing rights continued to be granted.
The main island was described in the Dublin Penny Journal in 1834:
"The Island of Dalkey ... is divided from the mainland by a channel called Dalkey Sound, in which ships may safely ride at anchor in eight fathoms of water, sheltered by the island from the north-east wind, to
which every other part of Dublin Bay lies exposed.
The island is said to contain eighteen acres, and, although covered with rocks, is esteemed an excellent pasturage for cattle of all kinds. It is curious to see the people conveying black cattle hither from the mainland. They tie one end of a rope around the beast’s horns, and then tie the other end to
the stern of a boat, which is pulledwith oars in the direction of the island. By this means they drag the animal into the sea, and force it to swim after the boat across the sound, a distance of about a quarter of
Besides good pasturage, Dalkey island produces some medicinal plants, and there s a ruin on it, said to be that of a church, but (the belfry excepted) no lineament survives that would induce a person to suppose it the remains of a place of worship. I much doubt its having ever been used for one. The side of the structure where some traces of an attar might be sought for, presents no such appearance; but on the contrary, a fire-place and chimney are to seen where the altar should stand, had the building been for
ecclesiastical uses ... Dalkey Island is uninhabited, save by the military stationed in the batteries."
In 1913 the islands were purchased by Dalkey Urban District Council. Since then they have remained largely undisturbed. However, from their strong visual presence and due to public access, primarily by private boat but also by unofficial commercial operators, the islands are rooted in the identity of