Acheson, Robert (1763–1824), presbyterian minister and United Irish leader, was born near Clough, Co. Antrim, son of James Acheson, farmer, and his second wife, Elizabeth; her brother Thomas Reid was minister of Glenarm, Co. Antrim. Robert Acheson graduated in medicine from Edinburgh University and practised for a time in Coleraine, Co. Londonderry, where he married his cousin Elizabeth Smith of Spittal Hill. However, he decided to become a minister, and studied theology in Glasgow University; on his return to Ireland, he kept school for a time before being ordained (1792) as assistant to his uncle in Glenarm. He refused to sign the Westminster confession of faith, siding publicly with the exponents of the more liberal New Light theology. He was popular in Glenarm, often providing free medical advice for the poor, and in June 1798 took command of the local contingent of United Irishmen assembled at Bellair Hill near the village. The yeomanry and a Scottish regiment arrested him and two other leaders, and he was held in Glenarm castle until an exchange of prisoners was arranged on 7 June 1798. On 8 June Acheson, in full military costume, was at the head of about 2,000 Glenarm men at Bellair Hill, but when news came of the defeat of the United Irishmen at Antrim, the camp at Bellair broke up in disarray, and all fled. Acheson was quickly arrested and court-martialled in Belfast on 28–9 July 1798. He conducted his own defence effectively, and several witnesses deposed that he had been trying to persuade the Glenarm men to disperse peacefully, but Acheson's acquittal is said to have been due to the interposition of his uncle Thomas Reid, whose Masonic connections were influential, and also to the good offices of the president of the court, Col. Leslie of the Monaghan militia, with whom he may have had family connections. Reid refused to take his nephew back as assistant, and Acheson was installed 20 June 1799 in Donegall St. congregation in Belfast. There he remained until his death; he kept a school and contributed to the Belfast Monthly Magazine, a periodical that maintained something of the liberal and even radical views of the middle-class supporters of the United Irish movement. Acheson died 21 February 1824; his widow and their five daughters and one son survived him.
Charles Dickson, Revolt in the north: Antrim and Down in 1798 (1960), 224 in 1997 ed.; Felix McKillop, Glenarm a local history (1987), 31–3; Alex Blair, County Antrim characters, i (1993), 6–7; I. R. McBride, Scripture politics . . . (1998), 205