Wes Craven was in part inspired by an incident that happened to him while taking a motorcycle trip with his wife. When they stopped in a small Nevada town, a trio of locals shot an arrow past his head and insulted him. When Craven threatened to sue them, they replied they could easily kill him, leave his corpse in a nearby salt mine, and no one would ever know.
The similarities to Blutgericht in Texas (1974) were intentional. Wes Craven was a huge fan of Tobe Hooper's film. He considered his film in part an homage to it.
(at around 55 mins) Virginia Vincent's reaction to being shot was quite genuine as there was a mishap with the squib planted under her robe. The small explosion caused her a deal of pain and she was briefly taken to the hospital.
Wes Craven's original title for the film was 'Blood Relations'. Producer Peter Locke however disliked the title. Numerous titles were then considered and the film tested best under the title 'The Hills Have Eyes', though Craven himself initially disliked the title.
The MPAA initially gave the film an X rating, which would have relegated it to the porn circuit and severely hurt box-office returns. Wes Craven cut the film enough to secure an R rating. The original director's cut is thought to be no longer in existence.