Based on a novel by James Dickey, Deliverance begins with Lewis Medlock's taking his Atlanta businessmen friends on a canoe trip down the fictional Cahulawassee River in the hills of Georgia. Of course, the four men are "outsiders" in this rural area, and they are asked why they have come. The city men perceive the rural folks as the stereotypical "hillbillies" who are genetically deficient (inbred), degenerate, mentally diminished, culturally deprived, malnourished with bad or missing teeth, and poor, yet content with where they are. In Deliverance, they are also murderous.
The term hillbilly was first defined in a 1900 New York Journal article:
a Hill-Billie is a free and untrammeled white citizen of Appalachia, who lives in the hills, has no means to speak of, dresses as he can, talks as he pleases, drinks whiskey when he gets it, and fires off his revolver as the fancy takes him.
The hillbillies that Bobby and Ed encounter in the woods are mistaken by them for having a moonshine nearby. Because some moonshiners run the liquor through car radiators, they sometimes ingest antifreeze left in these radiators. This substance is, of course, harmful; it can cause blindness and possible injuries to the brain. But, it is not so with them as the deputy sheriff later states that his brother-in-law went hunting and is missing.
At the beginning of the film, Lonnie, a mentally deficient, inbred albino boy who appears to be a "musical savant" joins in with Drew in an impromptu jam session of a bluegrass tune. As the men play, a tall, thin man wearing overalls and a floppy hat "clogs" to the music.