Factual error: Professor Harold Hill asks the mothers of River City about their sons, "Is he starting to memorize jokes from 'Captain Billy's Whiz Bang?'" While the film is set in 1912, the first issue of the pulp magazine, "Captain Billy's Whiz Bang," did not appear until 1919. "Whiz Bang" was a term coined by soldiers in World War I (commencing in 1914), which referred to a rocket that "whizzed" by and exploded with a "bang."

Continuity: In the beginning when the Anvil Salesman gets on the train, he sits down, arms to the side, the camera angle changes, and his arms are immediately on his hat adjusting it.

Continuity: As Shirley Jones is singing "In love with Me" at one point, she's sitting down, and is slouching back. The shot changes to the side, and she's sitting up straight, and is much higher against the counter than she was. Her hands have changed position as well, she's no longer holding onto the cup she had in her left hand.

Revealing: At a certain point we see the arid, dry Santa Monica Mountains of Los Angeles in the upper left of the picture with a huge high-tension electrical tower at the summit. The film is set in 1912 in Iowa, a green, rainy state which is also completely flat, with no mountains, due to glaciation in the last ice age. Then again, we see the arid, dry Santa Monica Mountains in the upper right.

Revealing: During "Marian the Librarian," Marian is seen doing a little dance on the table before being hushed by the people in the library. Like the incident with Winthrop in "Gary, Indiana," you can see that she did not actually do this dance. Tap sounds were added in later to make it seem like she did.

Revealing: At the end of Winthrop's version of "Gary, Indiana," we see what appears to be a little tap dance done by Winthrop that concludes the song. Upon close observation, however, you can tell that Winthrop does not actually do this dance. He just twirls around and tap noises are added in to make it seem like he is tapping.

Audio problem: If you listen carefully during the conversation between Marian and Ameryllis before "Goodnight, My Someone," you may notice something quite strange. After she is comforted by Marian, Ameryllis asks her, "If A GIRL doesn't have a sweetheart, who's HE going to say goodnight to on the evening star?"

Visible crew/equipment: During the song "Wells Fargo Wagon" film equipment and lights can be seen reflected in the store windows.

Continuity: After "'Till There Was You," Harold and Marian kiss. A shot of their reflections in the river shows this happening, and then it shows their heads part. When the shot changes to a close up of them they are kissing again.

Audio problem: During the first scene where the traveling salesmen are on the train, one of the characters says "He don't know one note from another". You can then hear a woman's voice laughing, even though there are only men on the train.