Here are some contenders, with explanations:
* The Cure for Insomnia (1987): This experimental film by John Henry Timmis IV clocks in at 85 hours (over 3.5 days). It's a single, continuous take, making it one of the longest films by runtime. However, it's considered an experimental art piece rather than a conventional narrative film.
* The Saddest Music in the World (2003): This Canadian film by Guy Maddin features an intertitle that claims it's 4 hours and 33 minutes long. It's a surreal, highly stylized film with a unique structure. While long, it's shorter than "The Cure for Insomnia."
* The Wandering (1947): This American film was originally 4 hours and 45 minutes long, but was later cut down for commercial release. It's known for its episodic nature and its experimental storytelling, which might make it a contender for "longest" in terms of narrative scope.
* The Lord of the Rings: The Return of the King (2003): At 3 hours and 21 minutes, this film is the longest in the "Lord of the Rings" trilogy and was the longest theatrical release in its time. It's a mainstream blockbuster, making it arguably the longest "movie" in the conventional sense.
Ultimately, the "longest North American movie" is subjective and depends on what criteria you prioritize.