Redneck is a derogatory term mainly, but not exclusively, applied to white Americans perceived to be crass and unsophisticated, closely associated with rural whites of the Southern United States.
The term may come from the look of a sunburned neck
Poor white sharecroppers in Alabama, 1936
Cracker, sometimes cracka or white cracker, is a racial epithet directed towards white people, used especially with regard to poor rural whites in the Southern United States. Although commonly a pejorative, it is also used in a neutral context, particularly in reference to a native of Florida or Georgia.
"A pair of Georgia crackers" as depicted by illustrator James Wells Champney in the memoir The Great South by Edward King, 1873
A "cracker cowboy" with his Florida Cracker Horse and dog by Frederic Remington, 1895