Situated directly north of Howth village and harbour, the island is easily reached by regular seasonal tourist boats, which both circumnavigate it and drop off day trippers.

It is home to nationally significant bird populations, notably of guillemots, razorbills, kittiwakes and cormorants, as well as gulls, and also including modest numbers of puffins and peregrine falcons.

[18] Ireland's Eye and its associated rocks are formed from Cambrian quartzite and greywacke, notably visible in the steep cliffs on the northern and eastern faces of the main island.

[20]: 9 In a survey in 2016, 11 land habitats and 4 maritime were identified; the marine aspect includes both intertidal and subtidal reefs, on the eastern edge of the island and in nearby waters.

Near the beach are also found prickly saltwort and the rare and "near-threatened" henbane, and in an area of coastal grassland, Portland spurge and the spring squill.

[20]: 13 The two historic buildings form a habitat zone of their own, and feature plants such as wall barley, sea fern-grass, dog-rose and dandelion, with the vicinity of the church also holding common orache.

[21] In the area of damp grassland around the natural spring site are plants typical of such terrain, and others fitting the marsh profile, indicating a history of greater waterflow.

[21] The major fire of 2015, which especially affected the southeast of the island, allowed a few specific plants, such as changing forget-me-not, sticky mouse-ear and prickly sow-thistle, to flourish.

[23] In the 18th and early 19th century, goshawks were noted as building their nests here,[24][25] but they are not listed in modern bird surveys covering Ireland's Eye.

At least 17 passerine species have been counted, 8 definitely breeding on the island; examples include the hooded crow, rock pipit, stonechat, wren, blackbird and reed bunting.

[20]: 38  There is also a population of brown rats, against which control measures are supposed to be carried out annually,[20]: 50  and there are rabbits, burrowing primarily in dry grassland areas.

One spider species, Tegenaria domestica, is mentioned in scholarly papers – it is a common domestic variety, which may speak to past habitation.

[26] A study of areas of scientific interest in County Dublin recorded the presence of notable ant populations in western Ireland's Eye and Red Rock on Howth Head.

[27] The aberrant ants, not isolated individuals, but occurring in some numbers, were found near a pool, and were studied for signs of radioactivity, but the cause of the issues was not determined.

The three, Munissa, Neslug and Dichuill, "men of exceptional piety, love and peace", arrived at a point between 570 A.D. and the late 7th or early 8th century, with the probable timing partly depending on the estimation of their descent.

[9] Ireland's Eye was a possession of the Bishop of Dublin, and later the archdiocese, as confirmed by Pope Alexander III to Saint Laurence O'Toole.

[31] In 1833 the island was occupied at least some of the time by a single water guard, and had a considerable population of foxes; it had been rented by a local for potential farming but abandoned as it was too difficult to cultivate.

There was no initial suspicion of foul play but questions were raised after some weeks, and her body was exhumed, and witnesses found who claimed to have heard screaming.

[34][35] Matthias McDonnell Bodkin claimed in Famous Irish Trials that no murder had taken place, and that Sarah Kirwan had instead drowned accidentally as a result of a fit.

No evidence of a broader settlement, such as a full monastery, has been found to date but scholars have noted that were secondary buildings made of wattle-and-daub, for example, traces might not have survived.

[9] The ruins of a church which probably began as a simple single-chamber chapel but which later took on a nave-and-chancel form, were subject to attempted restoration in the 19th century.

[20] The Martello tower, built in 1803 or 1804, was one of three constructed in the Howth area, and 26 in northern County Dublin, on the instructions of Prince Frederick, Duke of York and Albany to repel a possible invasion by Napoleon.

[20]: 27–28 The tower was rarely occupied, which contributed to poor maintenance, but there was a period during which it was a base, perhaps seasonal, for an early modern customs patrol body, the Preventative Water Guard.

[50] Ireland's Eye and its surrounding rocks and sea are incorporated within the Howth Special Amenity Area, which places some limitations on permitted development, and is overseen by a management committee with local authority and community representatives.

[20]: 40–41 A management document was prepared in 2017 by consultants working for Fingal County Council, with input from a wide range of stakeholders, and a public meeting in Howth village.

It comprised a study, summarising many sources about the island, and a prescriptive plan for 2018–2022, agreed between the owner, the local authority and some other stakeholders, including Conservation Volunteers Ireland.

This included agreement to make a one-off improvement to one of the landing places, to the east of the Martello tower, with installation of tying-up facilities, boats having been previously simply held manually near shore to allow disembarkation and embarkation.

Plans relating to the natural environment included triennial monitoring of vegetation, with some sampling quadrats maintained permanently, and annual removal or spraying of invasive plant species, as well as restoration of the spring and pond.

In the medium term it was planned to seek ways to conduct archaeological research, near the buildings and on potential promontory fort locations.

Some routes are no longer accessible due to shifts in the rock formations, guano build-up and bird population growth, notably on the Steer.