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.