The largest island off the east coast of Ireland, it is four kilometres (two nautical miles) offshore from the headland at Portrane, and is the easternmost point of the province of Leinster.

Steep cliffs lie along the northern, eastern, and southern coasts of the island, while the western side has low-lying land and gentle slopes.

Bedrock is a mix of andesite, tuff (from volcanic ash) and mudstone, as well as breccia,[9] but there are beds of shales and limestones also, and loamy soil.

There was also a stream to Seal Hole, which at least once had three rivulets meeting, one from Raven Well and two from marshy patches nearby, and finally, there was a flow from the vicinity of the castle to the sea near the harbour.

[21] The island supports one of the largest seabird colonies in Ireland, with more than 50,000 common guillemots, 5,000 kittiwakes, 3,500 razorbills, 2,500 pairs of herring gulls, as well as smaller numbers of puffins, Manx shearwaters, fulmars, and greylag geese.

[27] The earthworm aspect of the study found 34 species, of which 18 were previously unseen in Ireland, including the three new to science as a whole, and noted that the average size of specimens was smaller than on the mainland by a material amount.

[citation needed] In the 1st century AD the Ancient Roman writer Pliny knew about the island and referred to it as Limnus or Limni.

The finds included a number of Romano-British items, and the site has been interpreted as possible evidence for the arrival of a small group of refugees from Brigantia, fleeing the Romans from 71 to 74AD.

[34] St. Columba is reputed to have established a monastic settlement on Lambay c. 530 AD,[citation needed] which passed to Colman and a line of successor abbots and at least one bishop.

[35] Surveys in the early 20th century found remains of an enclosure to the south of the present chapel, and these, and modern satellite photography, suggested it was a moated site.

A later archbishop gave the rents of the island to the nuns of the Augustine Grace Dieu Abbey and school near Swords for the upkeep of their establishment.

In 1467, it was provided by statute that the Earl of Worcester, then Lord Deputy, be granted Lambay to build a fortress for England's protection against the Spaniards, French and Scots.

The island remained in the possession of the Ussher family, renting from the Church of Ireland See of Dublin, under Crown tenure,[36] for 200 years.

[38] On 21 January 1854, the iron-hulled RMS Tayleur struck the island's rocks and sank just hours into her maiden voyage from Liverpool to Perth, Australia.

In 1860 the existing farmers were removed by the Talbot family, who wanted to make the island a dedicated hunting ground, though they were later replaced with English and Scottish tenants.

[37] After selling his property, Portrane House, on the mainland nearby, Count James Consedine bought Lambay in 1888 to develop the island as a hunting retreat.

Baring, also a classical scholar and naturalist,[40] noticed it advertised for sale in The Field and bought it – for either £5,250 or £9,000 – for himself and his new bride, Maude, daughter of tobacco millionaire Pierre Lorillard IV.

The mausoleum, which was also designed by Lutyens, forms part of the circular rampart wall around the Castle and is engraved with a poem Cecil wrote in memory of Maude when she died.

Alexander Baring commented that he was engaged but isolated island life led to a break-off,[20][40] but he subsequently married and lives there with his wife and small children.

The application drew objections from several non-resident members of the family, who felt that it was too commercial in nature, and did not take enough account of the conservation needs of the buildings.

It is a joint venture between the island's holding company and the Camus Cognac family, which also had discussions with the owners of Slane Castle, who also launched a whiskey brand.

This identified a stone axe factory, using Lambay porphyry, near the centre of the island, and also made findings about burial of neolithic pottery and flint.

[52] After St Columba (Colmcille) from Ulster reputedly established a monastic settlement on Lambay in the 6th century, he passed its rule to Colman McRoi, later also a saint.

Some sources state that Colman, who is venerated by Catholic, Anglican and Orthodox churches, actually founded the monastery on what was then called Reachrain, with Colmcille's blessing.

A small late 16th-century fort with battlemented gables, possibly incorporating a 15th-century blockhouse, was transformed by Sir Edwin Lutyens into a romantic castle for the Hon.

[citation needed] Lutyens made the old fort habitable and built a quadrangle of kitchens, bathrooms and extra bedrooms adjoining it, with roofs of grey Dutch pantiles sweeping down almost to the ground.

Lutyens also designed the approach from the harbour, with curved step-like terraces reminiscent of the now-vanished Ripetta in Rome and a series of ellipses, circles being a long-standing symbol of welcome and also of wholeness.

Following previous ventures with sheep, including the Mayo Mule breed, the current flock is a cross of Texan and Blackface Mountain.

[32] The island has no power or communication cables from the mainland, and about 75% of its energy needs are supplied by solar panels, supported by a wind turbine, and with limited battery capacity and a backup generator system.

Captains Paul Armbruster and Louis Ansermier, from Switzerland, landed on the island after flying 756 km (470 mi) at a maximum altitude of 3,600 m (11,800 ft) during a flight of 27 hours and 23 minutes.