The burning house at the beginning of the film was a bit of serendipity for the film's crew. The local fire department was burning down an old house to practice putting out the fire, and agreed to let the filmmakers set up and film the event.
Filmed in Evans City and Connoquenessing Pennsylvania. Many of the movie's bit players were locals; several of the white-suited soldiers were actually high-school students.
No Hollywood stunt men were used in The Crazies. Local firemen and licensed fireworks professionals handled all of the action sequences, including the creation and employment of blood squibs.
The budget for The Crazies was approximately $270,000 and it was Romero's first Union film but he also employed a lot of actors from Pittsburgh and non-professionals from Evans City and Zelienople.
Years later, Lynn Lowry filmed a cameo in the 2010 remake.
S. William Hinzman: , the film's cinematographer, as the local who shoots at the fed's operation station.
George A. Romero: 2 cameos in the film; the first as a local being herded into the high school and the second as the head of the president of the United States seen on a monitor screen.