Remember, the sons had to wait until they were 21 to start naturalization. And daughters will not have been naturalized, as women didn't have the right to vote! Furthermore, you didn't have to be naturalized at all. If you are lucky, someone waited until the Declaration of Intent forms asked more questions. In the meantime, the 1900 census asks each person what year they came to this country, which might help you help the Area Research Center focus the search.
My gg grandfather and his son (18 ) were in the Civil war. I can't find naturalization papers for them. Was it possable that if they fought in the war they didn't have to have papers. My other g grandfather filed and got his papers 5 years after he arrived but he wasn't in the war. My g grandfather from England don't have naturalization papers either. He was a Minister for the Church of England and he was very involved with the underground railroad in PA. Was he exempt also? Thanks for any help, Thelma Thelma