Is there a plausible way to find out what the area corresponding to frazione D at that time was? There do not seem to be any current frazioni starting with the letter D, so I guess Voghera was repartitioned at some point.

Thanks so much! This helps a lot.

Hi, on the birth certificate of my GGF (Giovanni Giusto) there is a home address but I can't read it. It's in some frazione of Voghera, and looks like "Frazione D", but I could not find a frazione starting with D in Voghera. I also can't read any of the other stuff that's following "nella casa posta ...