Genealogical research becomes progressively more difficult as you get prior to:
1) the period when there are vital records such as birth death and marriage
2 the period of U. S. census record before 1850 when all members of a household are listed.
It depends on the individual states as the older states usually have vital records that
are older. Before 1850 we mostly depend on obituary files, land records, war records,
War pension files, bible records, church records, headstones, and tax records.
Surnames were invented 1300 to 1500 so it gets impossible then.
My usual email is:firstname.lastname@example.org