Lieutenant-General Thomas Mahon, 2nd Baron Hartland (12 August 1766 – 8 December 1835), styled Hon. Thomas Mahon from 1800 to 1819, was an Irish soldier, politician and peer. Son of a landed proprietor with an estate at Strokestown, he joined the British Army, serving for most of his career with the 9th Light Dragoons. His garrison skillfully ambushed and destroyed a force of United Irishmen at the Battle of Carlow in 1798. He briefly represented County Roscommon in the Irish and UK Parliaments as part of his father's successful scheme to obtain a peerage by supporting the Union, but this was not popular with the county electors, and he abandoned Parliament in 1802 to return to the military. He had the misfortune to be present at two military debacles of the Napoleonic Wars, the second invasion of the Río de la Plata and the Walcheren Campaign, and while he was not personally implicated in either, he saw no further notable military service. Mahon succeeded his father as Lord Hartland in 1819 and died without issue in 1835, his title and estates passing to his youngest brother.