Well this post isn’t about the census, but is relevant if you find someone who has emigrated to America. Many people who moved there were processed through the government department at Ellis Island and this website has an amazing database with millions of names of those from all round the world who were looking for a better life in a new country.
There is an urban myth which says that many people has their names changed during the emigration process by officials at Ellis Island to make them easier to say and spell for the english speaking civil servants. I read recently, and can’t remember where, that there is no evidence that this happened. Oh well another myth bites the dust!!