From The Art and Popular Culture Encyclopedia
A feature film is a film with a full-length running time. According to the Academy of Motion Picture Arts and Sciences, American Film Institute, and British Film Institute, a feature film runs for 40 minutes or longer, while the Screen Actors Guild states that it is 80 minutes or longer.
The majority of feature films are between 70 and 210 minutes long. The Story of the Kelly Gang was the first feature film based on length, and was released in Australia in 1906. The first feature-length adaptation was Les Misérables which was released in 1909.