Home » The largest prison in the world – Spike Island prison

The largest prison in the world – Spike Island prison

The opening of a Spike Island prison in 1847 was completely unexpected just six months before. The enormous island fortress that dominated its center was constructed in 1804, built to defend an Empire. It enjoyed a period of quiet domestic and international existence after the fall of Napoleon and the end of the Napoleonic wars. When Britain faced no immediate replacement for the threat of French invasion, work on the enormous twenty four acre fortress dried up.

With little building work or defensive duties after 1820, the island became a place of quiet service and solitude, but not before well over a billion Euro in modern money was spent on fortification.

The 1841 census of Spike Island showed just 202 persons resident on the island, consisting of military personnel and their families. This represented the lowest figure it would reach for the next one hundred and twenty years. An event on the mainland in 1845 changed everything in Ireland, and its effects are still felt to this day – the arrival of a severe potato blight and subsequent famine.

Skibbereen 1847 – one of the hardest hit towns in Ireland during the famine – by James Mahony

The horrors of the famine are far beyond the scope of this post, as are examining the impacts the death of one million people and the emigration of one million more on the Irish psyche. The famine impact on Spike Island was a rapid conversion of its fortress to prison use, the result of a desperate need for prison spaces arising from the sudden and massive increase in crime and convictions.

Crime of course is the wrong word, a moniker imposed by apathetic British rulers. Theft for Ireland’s famine victims was a matter of life and death, but the social and legal system of the time shamefully tagged them as criminals, ignoring the circumstances of their plight. The failure of British authorities to provide the necessary relief when there was ample food in the country suggests the real criminals of the time went unpunished.

There was a four fold increase in crime over a short period, with 10000 reports of cattle and sheep stealing and 1200 reports of plundering provisions. Petty crime like stealing potatoes and grain was on the rise, as was theft of items easy to sell for quick returns like handkerchiefs, shawls and clothing.

The transportation system, where convicts were sent to Australia and elsewhere to labour in British colonies, was overwhelmed, unable to accommodate the numbers requiring transportation. The name Spike Island began to be spoken of as the solution to a British problem again – not one regarding the coastal defense of an Empire, but this time as the solution to the problem of Irish incarceration.

An aerial image of Spike Island from around the 1930’s. Most of the 19th century prison features remain, with only the timber prison and iron prison removed.

A hasty conversion of the prison was completed in 1847, and soon it housed 608 prisoners. But remarkably, in just five short years it became the largest known prison in the entire world. 1200 packed its cells by the end of 1848, and over 2000 by 1851, but the peak was only reached when the number climbed above 2400 in 1853, six years after its opening. A staggering 60% of Ireland’s male convict population was being held in one cramped island location. This was a prison of a scale the world had never seen before.

Dublin’s Mountjoy Prison was considered large when it opened with five hundred prisoners in 1851, barely 25% of Spike’s number. New York’s Sing Sing Prison held 1600 prisoners around the same period, and was considered a behemoth of the age. Alcatraz Island held just over 1500 prisoners in its entire thirty years of existence, 40% less than Spike Island had at any one time. The typical compliment of 200 – 300 inmates at Alcatraz Island was a fraction of Spike Island’s peak, approximately 90% less.

In fact the number of 2300 prisoners is so large, it has never been surpassed before or since in Ireland or Britain, despite Britain’s population in particular being many multiples larger now. It was to all intents and purposes the worlds first super prison. Larger prisons have subsequently opened in the United States and France, although many are in the process of closing as the inherent issues with this scale have become apparent.

This 1870’s map shows the penal set up, with several areas still in use for incarceration.

Conditions on Spike Island were nothing short of horrific in those early days, and improved little in later decades. The massive over crowding saw as many as eighty men to a room as soon as the prison opened, with no separation in the busy dorms of the forts ‘A’ block.

As numbers swelled, new areas were hastily opened, like the timber prison, which had an unbelievable two hundred men per room. They were separated by a guard room in the middle, and a second room of two hundred occupied the other side. When a riot broke out in the block in 1849, men scrambled over the walls to join the melee. It was barely controlled chaos.

As the prison authorities had no formal solitary cells on the island, they had to improvise. They chose a location that could be described as the pits of hell, but without the heat of its fires. Underneath the forts walls, a warren of deep tunnels were constructed in long, dark corridors. They led to rooms for storing the forts gunpowder, safely underground away from cannon fire.

Around the rooms a clever lighting tunnel was created, where a live flame lamp could be placed in a window looking into the room. The glass kept the flame away from the gunpowder and stopped the fort being blow sky high. It was a labor intensive but ingenious solution to an age old military problem.

A tour guide showing the lighting window in the depths of the Spike Island tunnels. Photo Joleen Cronin

The tunnels were by their nature dark and damp, permanently cold at 12 degrees being under 100 feet of soil and stone. It was here at the very rear of this warren of tunnels that the solitary cells were placed. Inmates we’re held for up to twenty three and a half hours a day in total darkness. It was a cruelty that later newspaper reports would equate to medieval torture, its ethos not far removed from pure punishment.

When the cells were replaced in the 1850’s with a purpose built solitary confinement cell area, it was even named the ‘Punishment block’! Prisoner reform was being tried and tested elsewhere, but it had yet to make its way across the water to Spike Island Cork.

The Punishment block on Spike Island – Its ornate red brick interior holds 28 solitary cells.

These cramped conditions had the obvious effect of increasing the death rate, and the figures were equally astonishing and appalling. The first signs of trouble appeared when fifty two inmates died in 1850, one a week. By 1851 it was 122.

In 1852, 190 convicts died, and in 1853, the number was 286.  Two hundred and eight six men and boys, flesh and blood individuals, sent to an island prison to be reformed. Instead, they were dead and forgotten, while in the care of the State. 

To come to terms with a number is almost impossible.  Given the prisoner population that year, this means approximately 12% of the convicts held on the island died there that year.  These are hardly the kind of odds any of us would take with our lives, if given a choice in the matter.  Modern comparisons highlight the horrors, as even a prison as notorious as New York’s Rikers typically reports a death rate of 0.3%, making Spike Island’s death rate forty times higher.

The dark cells of the Punishment block, each windowless and furnitureless, with inmates chained to the wall for 23 1/2 hours a day.

Not far off a prisoner a day was being carted to the convict graveyard, which was rapidly becoming a swollen mass grave on the north side of the island.  Work on the Glacis a decade later would cover over this mass grave, of an estimated one thousand souls. A second mass grave began to fill at the far south west tip of the island from around 1860.  It was out of sight, out of mind, for Ireland’s unwanted. 

Things did mercifully get better. The crisis of the famine passed and convictions dropped, bringing some respite to the system. A review of the prison in mid-1850’s identified overcrowding as its primary dysfunction, and a decision taken nationally to immediately reduce the sentence of many crimes from seven years to four had a major impact. Of over one thousand offered immediate release due to time served, 683 were then housed at Spike Island.

The prison lost over a quarter of its prisoners almost overnight, and by the end of the year, just over 1400 prisoners were inside the forts walls. To coincide with the drop in capacity, the death rate fell 60% the same year, and continued to fall from almost a prisoner a day, to one a month.

Inside the Punishment Block, Spike Island

The wheel had turned, but it turned too late for over 1000 convicts, the number that died in the prisons first seven years. The majority of this number was accounted for in the awful period 1850 – 1854, a span that represents a dark stain in the fabric of Britain’s occupation of Ireland. It is one that was overshadowed by the unimaginable horrors of the famine years, with no person ever held to account.

A further three hundred souls are estimated to be buried in a second mass grave, which holds those that died in the prison between approximately 1860 until its closure in 1883. They lie in graves with no headstone or marker, buried in cheap pine coffins that their fellow inmates painted to look like more expensive oak. It represents a thin veneer of humanity for the convicts at the Spike Island prison, bestowed by their fellow inmates. T

The burial area was extensively excavated by archaeologists led by UCC’s Dr Barra O’Donnabhain, revealing its secrets. Dr O’Donnabhain is the co-author of ‘Too beautiful for thieves and pockets, written with multi-title author Cal McCarthy and published by Cork Library. Readers are directed to the work for the complete story on the incredible operation that was Spike Island’s Victorian era prison.

O’Donnobhain and McCarthys authoritative work on the Victorian era prison

Improvements did occur as the 1850’s progressed, and the period from 1855 until the prison closed in 1883 were different. In fact the Spike Island prison became part of a system of incarceration that would inspire penal efforts around the world, and still in use today.

The parole system was trialed and became widely accepted, after it was refined by the ‘father of parole’, Dubliner James Patrick Organ. He became the first Inspector of released convicts in 1855, and wrote and spoke on the societal benefit of planning the reintegration of prisoners.

A three stage approach was taken to incarceration, with the prison first serving approx nine months in single cell confinement in Mountjoy, to contemplate their actions. They then transferred to Spike Island to carry out the majority of their sentence, carrying out hard labor which was intended as reform. Some schooling and training in trade was part of this time.

An aerial view of Spike Island shows the scale of the twenty four acre fortress and prison, which dominates the 104 acre island.

Finally they were sent to an intermediary prison, like an open prison, where less stringent rules applied and they were prepared for reintegration with society. The Spike Island system and Irish system drew many admirers, and was adopted in many parts of the world, with the parole system in particular retaining regular use.

Spike Island Prison Chaplain, Reverend Charles Gibson, described the system so:

The prisoner is first crushed between the stone walls of a solitary cell, at Mountyjoy, where a little of the ‘mealy’ part of his nature appears outside the bruised and broken husk.  He is then forwarded to the working prison of Spike Island to be ground, where a good deal of the ‘chaff’ is taken out of him.  He is finally sent to Smithfield and Lusk to be ‘dressed’ for market”.  

The prison wound through the two more decades but calls for its closure came as early as the 1860’s. The military were keen to see the island returned, as works at nearby Naval Island Haulbowline made the need for adequate Cork Harbour defense more pertinent. The challenges and costs of an island prison, and the growing conflicting needs of the military, all combined to seal its fate. But not before some extraordinary characters had experienced its cells.

Read about some of Spike Island’s 19th century inmates here:


For the complete story of the Victorian Prison on Spike Island see – O’Donnobhain, B and McCarthy, Cal, Too beautiful for thieves and pickpockets – Cork County Library – 2016. This author first encountered its history in its amazing detail in this seminal work

For the complete history of the fortification of Cork Harbour and Spike Island see: Cal McCarthy – Cork Harbour – 2019, Merrion Press

Hughes, Robert. The Fatal Shore: A History of the Transportation of Convicts to Australia. London : Vintage books, 1987.

Gibson, Charles. Life Among Convicts, Volume 1 and 2. London : Hurst and Blackett, 1863.

Von Holtzendorff, Franz. The Irish Convict System. WB Kelly. 1860

Crimes of Convicts transported to Australia. Convict records.au. [Online] 03 2022. [Cited: 24 04 2022.] https://convictrecords.com.au/crimes.

Penal transportation records: Ireland to Australia, 1788–1868. National Archives.ie. [Online] [Cited: 25 04 2022.] https://www.nationalarchives.ie/search/index.php?category=18.

Guide to the Transportation records (Ireland to Australia) held by the National Archives of Ireland (as filmed by the AJCP): M2125-M2229. https://nla.gov.au/. [Online] 01 2022. [Cited: 15 03 2022.] https://nla.gov.au/nla.obj919437026/findingaid#:~:text=Between%201791%20and%201867%20about,had%20been%20convicted%20of%20larceny.

Content from upcoming release. May be quoted with credit and link. References in book or contact me, I love to discuss the subject. For further reading on the 19th century prison, the reader is highly recommended to discover 'Too beautiful for thieves and pickpockets' by Barra O'Donnabhain and Cal McCarthy.