United States Colored Troops
United States Colored Troops (USCT) were Union Army regiments during the American Civil War that primarily comprised African Americans, with soldiers from other ethnic groups also serving in USCT units. Established in response to a demand for more units from Union Army commanders, USCT regiments, which totaled 175 by the end of the war in 1865, constituted about one-tenth of the manpower of the army, according to historian Kelly Mezurek, author of For Their Own Cause: The 27th United States Colored Troops (The Kent State University Press, 2016).
Source: Wikipedia — United States Colored Troops (CC BY-SA 4.0)