I'm curious if anyone has tips on researching and confirming if you have a relative that was an undocumented immigrant from Ireland. For the longest time I've had a brick wall with my Bennett family. Recently I had a family member suggest my 2nd or 3rd great grandfather might have been an undocumented immigrant from Ireland. It is possible one of them entered the US from Canada since there are records of them being in Canada (but no immigration records) as well as records of them being in the US (Ohio, Missouri, Oklahoma, Alaska, Iowa). This would be in the 1850's to 1900 depending on which individual illegally immigrated. Beyond that conversation I don't have any hard facts to support this theory (especially since I have a birth certificate for my 2nd great grandfather that states he was born in Iowa and that his father (my 3rd great grandfather) was born in Ohio). I don't 100% trust the document stating that my 3rd great grandfather was born in Ohio since I have found no records of that and have done research with various Ohio genealogy groups with no luck finding him in Ohio.
Thanks in advance for any suggestions.
-darren