Major Adam Charles Muir (1770 – 11 May 1829) was an officer in the British Army, who played a significant but little-known role in the Anglo-American War of 1812. Muir was born in Scotland. The date is not definitely known; it may have been 1766 or 1770. He enlisted as a private soldier in the 41st Regiment of Foot in 1778. He was evidently well-educated and very quickly rose through the ranks, becoming a Sergeant in only five months and later Sergeant-Major, and being commissioned as an Adjutant in 1793. He became an Ensign shortly afterwards, and was promoted to lieutenant the next year. He served with the regiment in the West Indies.