I am the great-great grand daughter of James Johnston (abt 1797-1854) and Margaret Ligat (or Liggate or Liggett). James and Margaret married on May 12th 1834, and the marriage announcement in the Belfast Commercial Chronicle states " On the 12th instant, by the Rev. Robert Magill, Mr James Johnson, of Islandbawn, near Antrim, to Margaret, eldest daughter of the late James Ligat, Ballyrobin."
In 1838 the Rev. Robert Magill married Margaret's sister Ellen (or Eleanor, she seems to have been known by both names). She was his second wife, and the marriage announcement (Belfast Commercial Chronicle, June 18th 1838) said " On the 11th instant, by the Rev. Henry Cooke, D.D. LL.D., the Rev. Robert Magill, Antrim, to Ellen, second daughter of the late Mr. James Liggat, Ballyrobin, near Antrim."
Digging further into the records, Margaret and Ellen seem to have had two brothers: Abraham (born 1817), who was a presbyterian minister at Ballygilbert, and John (born 1821), who was involved in at least two court cases.
Abraham died in 1851, leaving a will which mentions his sisters, named as Margaret, Sarah, and Eleanor Magill. He also mentions his mother and his brother John, and an Uncle Alexander (resident in Lynchburg, Virginia).
John Liggett wound up in court in 1853 accused of "seducing" the daughter of a neighbour. In 1855 he was back in court, accused of so arranging his affairs as to appear insolvent and unable to pay the fine from the first case. There are several days of court reports available, from late July and early August 1855 (Owen O'Donnell vs Eleanor Liggat), as the courts attempted to determine who owned what. John's mother, Eleanor Liggat was the defendant in the second case, as the person in possession of a disputed farm. She was a widow in 1855, and stated that her husband had been dead for twenty years. There is some other detail of family members, which fits with what I have described above, except for one confusing statement made by one of the lawyers on August 1, 1855. The lawyer states that John's father was called Abraham Liggett, where I have been assuming that James Ligat was his father: "It was the property of Abraham Liggett, his father, and was left by him to another son, who, like a dutiful son, bequeathed it to his mother..." This does fit with the disposition of property in the Reverend Abraham Liggat's will - he did leave a farm to his mother, and he is mentioned in the court report as her deceased son.
My guess is that the lawyer made a mistake in his address. However, if anyone has any detail on this family - hopefully with better information than I have managed to extract from old newspapers - I would love to hear from you.