In general, the South of the United States has been less developed than any other region of the country. This can be seen, for example, in the fact that the four states with the lowest per capita income are Louisiana, Arkansas, West Virginia and Mississippi, with Mississippi having the lowest income in the nation. The same pattern holds for life expectancy in the various states. On that measure, the lowest four states are South Carolina, Alabama, Louisiana, and Mississippi. In fact, on this measure, the lowest 11 states are all in the South.
On some other measures, like unemployment, the South has improved relative to the rest of the nation, but it remains in many ways the least developed region of the country.