After immigrants were in the US awhile, it apparently became the fashion for them to name the nearest "big city" as their places of origin on censuses and certificates ---- especially among those living in large US cities who didn't want to look like they had been "country folks" or "farm hicks."
In my family, the Hannover became "Bremen" (which I think was actually an independent city-state and was never a part of the Kingdom of Hannover --- is that correct?), and the Prussia became "Koln" after 1880.
But I have no real way to know if either of those ancestors actually lived in those cities.
Does anyone else have some experience of this phenomenon to share with us?