The unit first gathered for training at
Trois-Rivières during the first half of 1812. During the later months of the year, the unit's companies were deployed to various locations in Upper Canada, to act as a nucleus around which the local militia could form in a crisis. On 3 October, two companies were stationed at
Prescott on the
Saint Lawrence River and were involved in a failed attack on
Ogdensburg on the American side of the river. The attack was called off when American artillery ranged in on the boats carrying the attackers. On 22 February 1813, George MacDonnell (who had been promoted to lieutenant colonel and appointed to command the garrison at Prescott) mounted another, successful, attack across the frozen river. In the
Battle of Ogdensburg, a company of the Glengarry Light Infantry and some militia made a frontal attack, while the main body of Macdonell's force turned the American right flank. The Reverend Alexander Macdonell was conspicuous in urging on the Glengarry soldiers and militia in their advance. A company was present at the
Battle of York but was able to play little part, as they were misdirected by the commander of the Upper Canadian militia. Another company suffered severe losses at the
Battle of Fort George, trying to prevent American troops landing on the lake shore to outflank the fort. Yet another company was present at the
Battle of Sackett's Harbor, where troops under Prevost and Baynes withdrew after failing to drive American troops from buildings and hastily constructed defences. During the later part of 1813, the entire regiment was concentrated around Fort George, and was engaged for several weeks in harassing the American outposts around the captured fort. The regiment was built back up to strength during the following winter. A company took part in the
Raid on Fort Oswego in the spring of 1814. During the following summer the full regiment, together with the light infantry companies of four regular line regiments, formed a covering force on the Niagara Peninsula, commanded by Lieutenant Colonel
Thomas Pearson. Later, on 25 July, the regiment formed part of a light infantry brigade under Pearson and played a major part in the
Battle of Lundy's Lane. They harassed the left flank of the American army but suffered casualties when mistaken for Americans by other inexperienced British troops. During the remainder of 1814, the regiment performed outpost duty during the unsuccessful
Siege of Fort Erie, and a detachment was present at the
Battle of Malcolm's Mills, the last action of the war on the Niagara Peninsula. Two Irish-born soldiers of the regiment, John Henry and John Blueman, are notable for their alleged involvement in one of
Toronto's most enduring historical mysteries – the 2 January 1815 murder of John Paul Radelmüller, keeper of the
Gibraltar Point Lighthouse. Tradition holds that Radelmüller was killed by several soldiers from
Fort York in a dispute over alcohol. Research by Eamonn O'Keeffe identified Blueman and Henry as the pair tried in March 1815 for the keeper's murder, although they were ultimately acquitted of the crime. The regiment was disbanded in 1816. Today, the regiment's history and service is commemorated by the Canadian Army's
Stormont, Dundas and Glengarry Highlanders, an Army Reserve regiment, headquartered in Cornwall, Ontario, which incorporates the title "GLENGARRY FENCIBLES" on its badge. To commemorate the 200th anniversary of the War of 1812, the regiment was awarded the NIAGARA battle honour earned by the Glengarry Light Infantry and NIAGARA is now among the 20 battle honours carried on the regimental colour of the Stormont, Dundas and Glengarry Highlanders. ==Uniform and equipment==