I have been playing with a website, GeoGen, that offers surname searches in a geographical genealogical context. You type in a surname of interest and the website generates a map showing areas of Germany where the surname is concentrated today. This can help guide you on where to look for records, but is not proof that any of your ancestors lived in any particular place.
Let's take Clara Patschke. She first appears in the 1870 United States Federal Census in Newark, Essex County, New Jersey, age 29, born in Prussia. Prussia does not exist anymore. As Clara was leaving Prussia to come to the United States, it encompassed a large area of land along the North and Baltic Seas. In the 1880 Federal Census, Clara provides a bit more detail about her origin: Saxony.
|1880 United States Federal Census|
Newark, Essex County, New Jersey
Someone kindly sent me an 1877 baptismal record for a daughter of Clara, listing Clara's origin as Zeitz, Saxony. There is a town called Zeitz in the Burgenlandkreis district of Saxony-Anhalt, which is next to Saxony, about 100 miles north of the modern border between Germany and Czech.
So we can plug in the surname Patschke at GeoGen to see where the geographic distribution of today's Patschkes.
Geographical distribution of surname Patschke
If we look at the area where Zeitz is located in Saxony-Anhalt, we see a concentration of Patschkes. This is where we would hope to find a lot of people with the surname.
Next we can look for variants of the last name using the Name Graph feature. Patschke was spelled differently on every record I have found so far. Seeing additional alternate spellings can help me uncover more records.
Name Graph for Patschke