54°48′59″N 5°43′39″W / 54.816358°N 5.727437°W / 54.816358; -5.727437 (Site of Knowehead House) The Islandmagee witch trials were two criminal trials in Carrickfergus in 1711 for alleged witchcraft at Islandmagee. It is believed to have been the last witch trial to take place in Ireland.

The events took place in and around Knowehead House in the townland of Kilcoan More in Islandmagee, a peninsula and civil parish in southeast County Antrim with a large Presbyterian population of Ulster Scots origin. The trial was the result of a claim by Mrs. James Haltridge of Knowehead House that 18-year-old Mary Dunbar exhibited signs of demonic possession such as "shouting, swearing, blaspheming, throwing Bibles, going into fits every time a clergyman came near her and vomiting household items such as pins, buttons, nails, glass and wool". Assisted by local authorities, Dunbar picked out eight women she claimed were witches that had attacked her in spectral form. During the arrest of the eight, they were set upon by a frenzied mob and one of the accused lost an eye. After the March 1711 trial and conviction of these eight, Dunbar had further attacks and blamed William Sellor. Dunbar died in April and Sellor was tried and convicted in September 1711.

The eight women were Janet Carson, Janet Latimer, Janet Main, Janet Millar, Margaret Mitchell, Catherine McCalmond, Janet Liston and Elizabeth Sellor. They were tried in March 1711 at the County Antrim spring assizes, presided over by two judges, Anthony Upton of the Common Pleas and James Macartney of the King's Bench. In their jury instructions they took radically different views of the evidence. Upton urged the jury to acquit: he did not take the modern view that there are no witches, but stressed the blameless lives of the accused and their exemplary attendance at Christian worship: was it likely that they also practised witchcraft? Macartney, however, took a more credulous view and successfully urged the jury to convict.

William Sellor, husband of Janet Liston and father of Elizabeth Sellor, was tried at the summer assizes in September 1711, and also convicted. No official records of the trials and verdict are known to exist; any that survived until 1922 were likely burnt in the destruction of the Public Record Office of Ireland during the Irish Civil War. The Witchcraft Act 1586 (28 Eliz. 1. c. 2 (I)) provided a penalty of death for causing death by witchcraft, and one year's imprisonment with time in the pillory for causing injury; it is likely that William Sellor suffered the former penalty and the eight women the latter. On release, all of the women were ostracized from the community.

In 2011, historians Victoria McCollum and Andrew Sneddon began a project to collect and review sources and commentary on the case. Sneddon comments on the lack of official sources and sparseness of other contemporary records, and accuses later accounts of introducing unsourced material which is then cited by still later sources. Sneddon has said that "Mary Dunbar was making up the whole thing" and that "Mary Dunbar learned the part of a demoniac from accounts about Salem or Scotland [as at Pittenweem and Paisley], or someone told her about it. Remember, this was a time when people were pouring in from Scotland".

Martina Devlin wrote a 2014 novel based on the case. Devlin proposed erecting a memorial to the eight women. Traditional Unionist Voice councillor Jack McKee objected that the plaque could become a "shrine to paganism"; he stated that he was unconvinced the women were not guilty and believed the proposal to be "anti-god". A plaque was eventually unveiled by Mid and East Antrim Borough Council at The Gobbins visitor centre in March 2022. The proposed line "Today the community recognises your innocence" was omitted from the inscription after Ulster Unionist Party councillor Keith Turner objected that it was ultra vires for the council to make such a claim and it should "let visitors decide themselves". David Campbell adapted McCollum and Sneddon's research into a 2023 graphic novel.

• Florence Newton, the "witch of Youghal" tried in 1661

• McCollum, Victoria; Sneddon, Andrew; Ferguson, Frank; Butler, Stephen; McCullough, Alice (18 December 2023). "Roundtable: The Islandmagee Witches 1711 Creative and Digital Project". Estudios Irlandeses. 18 (2): 112–118. doi:10.24162/EI2023-12229.
• Seymour, St John Drelincourt (5 September 2013) [1913]. Irish Witchcraft and Demonology. Dublin: Hodges, Figgis. pp. 200–221. Retrieved 24 March 2023 – via Gutenberg.org.
• Sneddon, Andrew (15 May 2013). Possessed By the Devil: The Real History of the Islandmagee Witches and Ireland's Only Mass Witchcraft Trial. The History Press. ISBN 978-0-7524-8087-9.
• Sneddon, Andrew (27 May 2019). "Witchcraft Belief, Representation and Memory in Modern Ireland". Cultural and Social History. 16 (3): 251–270. doi:10.1080/14780038.2019.1595273. S2CID 150681667.
• Summers, Montague (1927). The geography of witchcraft. London: Kegan Paul, Trench, Trubner. pp. 96–98.

• Witches of Islandmagee, by Victoria McCollum and Andrew Sneddon — primary sources and background information