This episode features a cheeky nod to the TV show that many initially claimed it aped, The X-Files (1993). As Dean walks past an investigating pair of FBI agents, he says "Hello Agent Mulder, hello Agent Scully".
This was the only episode of the show filmed in Los Angeles. The rest of the series has been shot in Vancouver, Canada.
In one version of the pilot script that Eric Kripke turned in to the studio, the episode ended with the Winchester boys finding their dad dead on the ceiling. In another version of the pilot script, Sam suspected Dean of being a serial killer, and of murdering their father.
The California town of Jericho is entirely fictional.