A company of the Glengarry Light Infantry was at the Battle of York, but didn't play a big part. 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 forces landing on the lake shore from outflanking the fort.
Yet another company was present at the Battle of Sackets Harbor where troops under Prevost and Baynes withdrew after failing to drive American troops from buildings and hastily constructed defenses.
During the latter part of 1813, the entire regiment was concentrated around Fort George and was engaged for several weeks in harassing American outposts around the captured fort.
They were built back up to full strength during the following winter (1813-1814). A company took part in the raid on Fort Oswego in the spring of 1814. During the following summer, the full regiment along with 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 role in the Battle of Lundy's Lane where they harassed the left flank of the American Army but suffered casualties when mistaken for Americans by other inexperienced British troops.
--Brock-Perry