The Greenville encampment is a notable site for African-American military history. In 1866, Major General Phillip Sheridan, commander of the Department of the Gulf, organized a regiment of African American cavalry, designated the 9th Cavalry Regiment. The 39th United States Colored Infantry Regiment Troops were also stationed in Greenville. The 39th Infantry was later consolidated with another unit at Jackson Barracks and redesignated the 25th Infantry Regiment. The 9th Cavalry and the 25th Infantry were two of the four units that collectively became famous as the Buffalo Soldiers for their activities in the West and during later conflicts.
During the Indian Wars of the late 19th century, Native American opponents, including the Cheyenne and Comanche, dubbed these aforementioned military units Buffalo Soldiers. These units fought in the Spanish American War, Mexican border disputes, and in World War II, prior to the integration of the Armed Forces in the 1940s.