Robert Christie Buchanan (March 1, 1811 – November 29, 1878) was an American military officer who served in the Mexican–American War and then was a colonel in the Union Army during the American Civil War. In 1866, he was nominated and confirmed for appointment to the grades of brevet brigadier general and major general in the Regular Army (United States) for valor in several battles, to rank from March 13, 1865. In a career that spanned more than forty years, Buchanan held numerous commands (including several forts) and received multiple citations for bravery and distinguished service.