Buchanan is a city in Stutsman County, North Dakota, United States. The population was 87 at the 2020 census. Buchanan was founded in 1887. Buchanan was once home to Henry Leuhr's Giant Bull, inspired by the World's Largest Buffalo in Jamestown, North Dakota, which stood 30 feet tall and was 50 feet long until it deteriorated and was removed from its site in January 2007.