This film was in the Guinness Book of World Records for "Top Budget: Box Office Ratio" (for a mainstream feature film). The film cost $22,000 to make and made back $240.5 million, a ratio of $1 spent for every $10,931 made.
The directors kept in touch with actors Heather Donahue, Michael C. Williams and Joshua Leonard with walkie-talkies, to ensure the three would not become lost during their trek. Reportedly, they got lost at least three times.
The three leads believed the Blair Witch was a real legend during filming, though, of course, they knew the film was going to be fake. Only after the film's release did they discover that the entire mythology was made up by the film's creators.
The reactions from Heather, Mike and Josh, when they discover they have walked south all day and ended up in the same spot, are real; they were genuinely upset that they had walked all day for nothing.
Heather Donahue admitted there was a considerable backlash against her because of her association with The Blair Witch Project (1999). It led to her having threatening encounters and difficulty finding other employment.
In a scene where the main actors are sleeping in a tent at night, the tent suddenly shakes violently and they all get scared. This was unscripted and the director shook the tent; the actors actually were scared.
Although having been given a brief crash course on using the 16mm camera, Joshua Leonard struggled to focus using it for the first few days of filming. This is why the interview with Mary Brown is of such poor focus and incredibly grainy.
To maintain the film's fear factor, the three main actors agreed to stay in character for the entire eight days of filming. Periodically, if an actor had to break from character, then the remaining two actors also had to break from character, but only after collectively reciting their safety word, taco.
The actors were given no more than a 35-page outline of the mythology behind the plot, before shooting began. All lines were improvised and nearly all the events in the film were unknown to the three actors beforehand, and they were often on-camera surprises to them all.
The filmmakers placed flyers around Cannes for the film festival that were "Missing" posters, stating that the cast was missing. All the flyers were taken down by the next day. It turned out that a television executive had been kidnapped just prior, and [the flyers] were taken down out of respect. The executive was since recovered safely.
The 1999-2000 hunting season suffered badly, due to this film. The movie was so popular that fans all over the country were hiking into the wilderness to shoot their own Blair Witch-style documentaries. As a result, they kept most of the wildlife scared away from hunting areas.
In the movie, Heather and Mike share a somewhat antagonistic attitude towards each other. In the commentary, the directors revealed it was Heather and Joshua who were arguing most of the time (and more heatedly). Almost all of the footage of their arguments was taken from the final cut, after the filmmakers decided it seemed like both men were "ganging up" on Heather.
The directors put up posters at a local college, in an attempt to recruit students to help work on this low-budget production. Only one person responded to the recruitment ad, and this was Patricia DeCou, who not only portrayed Mary Brown, but also helped with the art department.
The movie inspired a short-lived series of young-adult horror novels, written by an author under the name "Cade Merrill," who claimed to have been Heather's cousin and a longtime Burkittsville resident.
The runic lettering in the old house are a mixture of two different alphabets, Hebraic and Futhark. Hebraic runes went on to become Ancient Hebrew. Futhark runes are proto-European, dating from the first millennium B.C.
Sanchez and Myrick wanted Heather to have a sort of Captain Ahab quality (obsessively documenting everything). Heather Donahue had that. Mike's function in the film is to say the things the audience is probably thinking. And Josh (for a time) is the team peacemaker.
In the initial draft, Josh was intended to have a strong romantic interest in Heather. In several of the scene instructions given to the actors on the callback auditions, it was instructed that Josh take note of how attractive Heather was, and how dejected he should be that she seemed oblivious to this. Eventually the idea was scrapped as fear the movie would become too cliché.
Some theatergoers experienced nausea from the handheld camera movements and actually had to leave to vomit. In some Toronto theatres, ushers asked patrons who where prone to motion sickness to sit in the aisle seat and to try not to "throw up on other people."
When the movie was released the town of Burkittsville, in the hopes of making at least some profit from the film, did its own marketing. During the annual summer carnival the local Ruritan Club featured the "Bur-Witch" sandwich - country fried ham and a fried egg on top of a cheeseburger, nestled in a sesame seed bun, and doused with horseradish. The sandwich was the most popular selling item on the menu two years in a row.
Although Heather, Mike and Josh had to pitch and take down the tent they slept in, they did not have to carry it from location to location for them as this was done for them by the movie crew who would do so out of sight.
The two fishermen were father and son in law. Sanchez and Myrick toyed with the idea that one of them was playing a prank on the kids, like something out of Scooby Doo, Where Are You! (1969). They didn't follow through with it because it seemed a cheesy reason for all the spooky goings on.
According to the directors, the scene where Heather, Josh and Mike were in the motel room was the longest piece of film that the three had shot. The scene reportedly went on for at least ninety minutes and involved Josh and Mike reading poetry followed by some drunken arguing between Josh and Heather.
The real town of Burkittsville where the film is set found itself awash with fans. The town sign was stolen and desecrations in the graveyard made the mayor instigate extra police protection. The local cinema decided not to screen the film.
The sounds of children heard at night was taken from kids playing around the house of director Eduardo Sánchez's mother. The tape was played over boomboxes in the forest. According to Michael C. Williams, he found it the scariest scene to shoot in the film.
One of the first theatrical features to make use of a large-scale viral marketing, which claimed that the three main characters had really gone on a trip to shoot a documentary and were never found again, save for their video camera and the footage they shot. A website was posted on the Internet one year prior to the release to set up the premise of the documentary, complete with detailed reports of the search, the recovery of the trio's footage within an old cabin, reactions from their families, and expert opinions. The three actors were instructed to refrain from making public appearances. The myth wasn't debunked until after the movie's premiere, but positive word of mouth had already popularized the movie to the extent that its success completely overshadowed that of the almost simultaneously released big-budget horror movie The Haunting (1999).
The audition process was quite rigorous because the directors wanted actors with significant improvisational talents. Typically, the candidate entering the audition room would immediately be presented with a description like "you've just served 10 years of a 25-year prison sentence. Tell us why you should be due for parole". If the candidate hesitated to long, the audition would be over. Heather Donahue's response was "I don't think you should."
More money was spent on the movie afterwards than before its completion. The directors estimated the initial production budget of the movie to be around $20,000 and $25,000, but this rose to somewhere between $500,000 and $750,000 (over 20 times the original budget) after the studio did some additional post-production. The studio had acquired the movie rights for $1.1 million (over 40 times the original budget); they spent an additional $25 million to market it (over 1000 times the original budget). Even while taking into account these additional costs, with a worldwide box office of almost $250 million, the movie earned more than 9 times its final budget.
The film was originally planned to include both the story of the missing students as well as the aftermath of their disappearance. The found footage of the trio would be framed by newscasts about the search for them, as well as interviews with family members and experts. Most of this material was cut out during editing for feeling contrived and too scripted, in favor of focusing completely on the story of the three students. However, much of the deleted material could later be used in the viral marketing of the film.
The final day of shooting took place on Halloween night. The crew had planned on wrapping one day before, but the camera had run out of batteries due to the camera light, requiring an additional day of shooting.
Although the concept of a movie consisting of people's recovered video recordings is not new (with Cannibal Holocaust (1980) as a notable early example), 'The Blair Witch Project' managed to reinvigorate the 'found footage' style of filming for several decades to come, inspiring other horror movies like Paranormal Activity (2007), [Rec] (2007), and The Last Exorcism (2010), but also non-horror productions such as Cloverfield (2008), Chronicle (2012) and Project X (2012).
When Heather screams "What the **** is that?!" she is seeing one of the movie crew standing on a hill dressed in white with a ski-mask on. Josh was holding the camera as ran behind her and didn't manage to catch the image on film.
Other endings shot in post-production that were scrapped included Mike being hanged, another had him bound to the wall with twigs in the manner of a stick figure. Stick figures themselves were experimented with as decorations in the final scene.
Heather Donahue's discovery of Joshua Leonard's teeth, blood and hair wrapped in a bundle of twigs bears a striking similarity to Washington Irving's story "The Devil and Tom Walker". Tom's wife goes to find the devil in the swamp, and never returns home. When Tom goes to find her, he discovers her apron with her heart and liver inside. However, it also reflects a scene in the silent documentary "Haxan" where a severed hand is carried by a witch hidden in a bundle of twigs.
This film was one of the most pirated films of 1999 because of limited release due to its independent status. The pirated version was an unfinished leaked work-print with several plot holes and most of the initial interviews missing leading to audience confusion at final scene of the film.
The close-up of Heather Donahue's face as she tapes her farewell video was unintentional. Donahue planned to have her whole face in frame, but she had zoomed in the camera too much. However, the directors thought that the 'closeness to all the tears and phlegm' really added to the 'ugly realism' of the scene, and kept it in.
Heather Donahue and Michael C. Williams were unaware that Joshua Leonard was going to disappear near the end of the shoot (originally Williams' character was supposed to do that). The directors had left a note for Leonard instructing him to wait for the others to fall asleep, and then leave the tent. They had to wait for 45 minutes before calling him out, telling him "you're dead." Leonard was actually glad to leave because there was a Jane's Addiction concert he wanted to go to.
Originally, it was Mike (Michael C. Williams) who was supposed to disappear near the movie's end. However, throughout filming, there was so much bickering going on between Heather (Heather Donahue) and Josh (Joshua Leonard) that it started to become annoying and disruptive. So it was decided to pull Josh out prematurely, and most of the Heather-Josh arguments were edited out in post-production, focusing more on the antagonism between Mike and Heather. This choice proved advantageous, as Mike was always intended to be the antagonist of the group, so leaving him and Heather as the last two survivors created extra tension due to their different personalities.