Horace is a city in Cass County, North Dakota, United States. In 2016 the population was estimated at 2,652. From 2000 to 2010, Horace was the fastest-growing city in North Dakota in terms of percent increase, increasing 165.6% over that decade from a population of 915 in 2000.The city is a suburb of the Fargo-Moorhead metropolitan area. It is the nineteenth-largest city in North Dakota. Horace was founded in 1882 at a time of widespread European-American settlement in the territory.