As in almost all Southern states during the American Civil War, a number of units were raised to fight for the Union Army, from pro-Union citizens and former slaves. North Carolina provided approximately 15,000 troops who served in Union Army regiments. About 10,000 white North Carolinians served in four white North Carolina Union regiments, and 5,000 black North Carolinians served in four black North Carolina Union regiments. During this time period, regiments of the United States Army were segregated by race. Other men would leave the state to join other Union regiments, and there were also Confederate Army deserters from North Carolina who later fought for the Union.