Pine Bluff was prospering by the outbreak of the Civil War; most of its wealth was based on the commodity crop of cotton. This was cultivated on large plantations by hundreds of thousands of enslaved Africans throughout the state, but especially in the Delta. The city had one of the largest slave populations in the state by 1860, and Jefferson County, Arkansas was second in cotton production in the state. When Union forces occupied Little Rock, a group of Pine Bluff residents asked commanding Major General Frederick Steele to send Union forces to occupy their town to protect them from bands of Confederate bushwhackers. Union troops under Colonel Powell Clayton arrived September 17, 1863 and stayed until the war was over.