I'm German in derivation "up to here". The "here" being at the outboard ends of the strands of my hair.Now as to what part of modern Germany, my maternal grandfather was proud of being "A good Holsteiner." For the polico-geographically impaired, that's northern Germany, up near Denmark.
My last name, Oesterreich, is the German word for Austria, and I suppose it is to be presumed that way back some direct male ancestor was from Austria, and that would place the route of family development, so to speak, through southern Germany.
My maternal grandfather and grandmother were born in the US, maybe around 1880, but raised speaking German, Germanic culture. By the time I came along they seldom spoke German except when "die kinder" shouldn't hear.
Dave Oesterreich