Germany has many "cultural regions" and "geographical landscapes", smaller, informal areas that were not political entities, for example, "The Black Forest" or "Frisia". Your ancestors might have left records or family traditions that they were from one of these areas. This list of [http://wiki-de.genealogy.net/Kategorie:Landschaft '''"landscapes" by GenWiki'''] can help you identify these regions. Once you know that the information is a cultural region not a town, you will know that you need to search further to narrow down your ancestors' town.
==Details in Major Gazetteers==