William Conyngham Plunket, baron, an Irish lawyer, born in Enniskillen in July, 1764, died Jan. 4, 1854. He was the son of a Presbyterian minister, graduated at Trinity college, Dublin, obtained a scholarship, entered Lincoln's Inn in 1784, was called to the Irish bar in 1787, and became king's counsel in 1798. When the rebellion broke out he gave professional aid to the patriots, and was publicly accused of being an associate in their proceedings. In the Irish parliament, to which he was elected in 1798, he opposed the legislative union with England in 1800, and his speeches in the debates on that measure raised him to the first rank of his party and greatly increased his practice at the bar. In 1803 he was made solicitor general for Ireland, and on the outbreak of Emmet's rebellion was one of the crown lawyers for the prosecution. In 1805-7 he was attorney general for Ireland. From 1807 to 1822, with a brief interval, he was in the British house of commons, and made several able speeches in favor of Catholic emancipation. He was again made attorney general for Ireland in 1822, and one of his first official acts was to prosecute a large number of Orangemen for riot. In 1827 he was made chief justice of the common pleas in Ireland, and was ennobled.

From 1830 to 1841 he was, with an interval of five months in 1834-'5, lord chancellor of Ireland. He passed the rest of his life in retirement at his seat in Wicklow co. An edition of his speeches, by J. C. Hoey, was published in 1856, and his "Life, Letters, and Speeches," edited by one of his sons, with a preface by Lord Brougham, in 1867 (2 vols. 8vo).