The UN General Assembly Human Rights Council 2018 report on USA’s poverty and human rights is a pretty quick and clear overview which makes it clear that parts of the USA are just undeveloped:

http://undocs.org/A/HRC/38/33/ADD.1

“5.3 million live in Third World conditions of absolute poverty”

“69. In Alabama and West Virginia, a high proportion of the population is not served by public sewerage and water supply services”