The idea for Willow Creek originated when Goldthwait visited the real Willow Creek with plans on making a "Christopher Guest-like" movie set during a Bigfoot convention. He decided that making fun of believers "wasn't a nice thing."
Goldthwait isn't actually a fan of found footage films because "who found this footage, you know what I mean, and made a movie? I'm sorry your family got raped to death, but I think if I re-cut it there's a tremendous picture here."
The script was essentially a twenty-five-page outline. Goldtwait figures nearly eighty percent of their dialogue is improvised.
The "one take" tent scene is 18 minutes long.