The primary reason for the settlement of more African Americans in the Mississippi Alluvial Plain region compared to the Ozark Mountains region was slavery and plantations.
The Mississippi Alluvial Plain, particularly during the 19th century, was characterized by a thriving plantation economy that relied heavily on slave labor to cultivate cash crops such as cotton and sugar. This system created a significant population of enslaved African Americans in that region. In contrast, the Ozark Mountains were less suited for large-scale plantation agriculture and had a different economic focus, leading to fewer African Americans settling there.