After reading this document not all Naturalization documents provide a cut path to the 'old country' Most are as vague as this one from Des Moines County
City Directories are, in my opinion, a very good resource.
City Directories are, in my opinion, a very good resource.
Death Records are another resource that genealogists glean informative tidbits from that lead to yet another set of questions.
Brothers, Cousins, what documents are you willing to add?
