The Under-Secretary for Ireland (Permanent Under-Secretary to the Lord Lieutenant of Ireland) was the permanent head (or most senior civil servant) of the British administration in Ireland prior to the establishment of the Irish Free State in 1922. The Under-Secretary's residence was at Ashtown Lodge in Phoenix Park, also known as the Under Secretary's Lodge. Among the best-known holders of the office was Thomas Henry Burke, who was assassinated along with the Chief Secretary for Ireland, Lord Frederick Cavendish, in the so-called Phoenix Park Killings on Saturday, 6 May 1882.