The United States Colored Troops (USCT) were regiments in the United States Army composed primarily of African-American (colored) soldiers. Other people of color who were not of African descent, such as Native Americans Pacific Islanders, and Asian Americans also fought under USCT regiments. They were first recruited during the American Civil War, and by the end of that war in April, 1865, the 175 USCT regiments constituted about one-tenth of the manpower of the Union Army. At the height of its growth, the USCT comprised almost 180,000 men. The USCT was the precursor to the Buffalo Soldier regiments of the American Old West.