During production, director Don Bluth staged a demonstration of the difference between limited TV animation and the full animation used in the film. He had his staff stack up animation cels by his feet into two piles, one representing two minutes of limited animation, the other two minutes of full animation. The TV pile reached only to Bluth's shoelaces; the film pile went all the way up to eye level.
When Tony and Bridget emerge from the wreckage after the cat attack at the market, a bottle of "Pomeroy Hair Tonic", named after co-producer John Pomeroy, can be seen in the background.
A shot of a cat lunging towards the camera during the market attack is recycled from Don Bluth's previous film, The Secret of NIMH (1982).
Tom Bähler was originally approached to write the songs for the film, but soon left the project due to commitments with Quincy Jones on The Color Purple (1985).
When Gussie is making her speech at the rally, she stands on a can of "Dorse Hair Restorer", named for crew member Dorse A. Lanpher.
CASTLE THUNDER: The first clap of thunder as the storm hits the boat
The opening scene of the ship's arrival in America (at Castle Garden) is based on a photograph in Christian Weekly magazine from March 28, 1874. On the barge is written, Einwanderer Beforderung, which means "Immigrant Transfer" in German.