There has always been a family tradition that my mother was Jewish. My mother even has recollection on her mother and her mother's mother using specifically Jewish terms, such as referring to "Hashem" when talking about G-d. Another example of the tradition's legitimacy is the fact that my mother's family never belonged to a religious institution, and oftentimes declined invitations to churches and such. (In the place where they lived, there was no synagogue.)
(Because of the tradition, I have been raised all my life with a Jewish upbringing.)
However, I have been having some trouble locating the roots of the tradition. I tried JewishGen, searching some of my ancestors' names, but to no avail.