|1st Lieutenant Governor of New Brunswick|
|Preceded by||Post established|
|Succeeded by||George Stracey Smyth|
|Died||2 February 1817 (aged 81–82)|
Ramsgate, Kent, England
|Resting place||St Swithun’s Church at Nately Scures, Hampshire, England|
Hannah Foy, née Van Horn (m. 1783)
Thomas Carleton (c. 1735 – 2 February 1817) was an Irish-born British Army officer who was promoted to Colonel during the American Revolutionary War after relieving the siege of Quebec in 1776. After the war, he was appointed as Lieutenant-Governor of New Brunswick, and supervised the resettlement of Loyalists from the United States in the province. He held this position until his death.
Born in Strabane, Co. Tyrone, Ireland to Christoper Carleton and his wife Catherine Ball, he was the younger brother of Guy Carleton, 1st Baron Dorchester. As part of a military family, Thomas joined the British Army at a young age.
In 1753, he was an ensign in the 20th Regiment of Foot and saw action with his regiment during the Seven Years' War. After the conclusion of the Seven Years' War, Thomas Carleton served as an observer during the Russo-Turkish War of 1768–1774.
In 1776 during the American Revolutionary War, as a lieutenant colonel, he arrived in Quebec City with forces to relieve his brother, Sir Guy Carleton, the Governor General of Canada, who was besieged in the city by Continental Army troops. With the death of Lt. Col. Patrick Gordon on July 25, 1776, Col. Carleton was promoted to command the 29th Regiment of Foot. In 1777, Thomas Carleton's nephew Christopher Carleton joined the 29th regiment as a major and served under his uncle's command for the rest of the war. Col. Thomas Carleton did not get along well with his new commander, Frederick Haldimand, who replaced Guy Carleton in 1778 as Governor General of Canada. He refused when in 1782 Haldimand demanded that he resign his position as quartermaster general before his planned departure for New York, where his brother Guy had replaced the disgraced Henry Clinton. Thomas Carleton returned to England where he lodged with Lord Shelburne, who at the time was First Lord of the Treasury and Leader of the House of Lords.
In summer 1784, with the administration of Government safely under Shelburne's colleague Pitt the Younger, Col. Thomas Carleton was appointed as the first Lieutenant-Governor of New Brunswick. Here, he helped to re-settle the many Loyalists leaving the United States. He was made Major-General in the regular army on 12 October 1793, and colonel commandant of a battalion of the 60th Foot in August 1794.
Carleton saw off a censure motion and attempted ouster by some assemblymen, led by James Glenie, in the closing years of the 18th century; but Glenie had been found guilty in 1780 by a court-martial board, which included Carleton, "of having behaved unbecoming the Character of an Officer and a Gentleman on many occasions", and so future events between the two would necessarily have been poisoned.
Carleton would serve as Governor of New Brunswick until his death on February 2, 1817. In 1803 he departed for England and administered from there, as he never returned to the province.
Of Carleton and wife Hannah Foy (née Van Horn) were born son William and daughters Emma and Anne. Stepson Captain Nathaniel Foy was born to Hannah in her first marriage.
Mount Carleton, the tallest mountain in New Brunswick, is named for him.