Lacking a reliable source of water, the earliest settlers avoided farming the black soil in the belt until the discovery that deep artesian wells could be drilled to supply water for people, livestock, and crops. Beginning in the 1830s after Indian Removal, cotton plantations were developed that produced the commodity crop that became Alabama's greatest source of wealth. Before the American Civil War, these plantations were worked by thousands of African-American slaves. The Black Belt region had the highest density of population in the state and was majority-black.