In the spring of 1699, Margaret Supp, a resident of the Port Glasgow and Kilmacolm area, became ensnared in the periphery of a significant witchcraft investigation. Her connection to these events originated in the testimony of Margaret Murdoch, the daughter of John Murdoch of Craigtown, who claimed to be suffering under the influence of various local witches. As the young girl identified numerous individuals across the region, her accusations drew the scrutiny of both medical professionals and a group of ministers, who examined her claims with rigorous attention.
By April 22, 1699, the focus shifted toward Margaret, as four individuals—one man and three women—provided testimony against her in Glasgow. Despite this formal mention in legal records and her association with Agnes Supp, another woman from the same locale, the available documentation suggests that Margaret did not face further formal prosecution. While the records confirm that she was suspected and named during this period of heightened anxiety, there is no evidence of a trial or subsequent sentencing, leaving the final outcome of her case a matter of historical ambiguity.