How can I find where in Alsace-Lorraine, France my family came from!?

Question:

How can I find where in Alsace-Lorraine, France my family came from!?

I know the names of my great-grandparents, when they came to the U.S.A., even the ship (for the kids and great-grandma, great-grandpa must have came before them, or more unlikely after them) but I don't know where they came from and no one in the family does, just that they said Alsace-Lorraine, France. Is the last name Hartman unique to any areas?

Additional Details

2 weeks ago
They came from Alsace-Lorraine when it WAS Alsace-Lorraine, during the German Empire rule. Also, I would never call their name German because apparently they caused hell for my family, they all had french first names and spoke french, hardly german. They came to the usa in 1888.

2 weeks ago
What on earth is LDS? Also, to the person about "Republican France", my great-grandparents were born in the mid 1850s, during the rule of Emperor Napoleon III, so idk if thats true of Alsaciens and Lorrains.

Best Answer - Chosen by Asker: 2 weeks ago
They came from Alsace-Lorraine when it WAS Alsace-Lorraine, during the German Empire rule. Also, I would never call their name German because apparently they caused hell for my family, they all had french first names and spoke french, hardly german. They came to the usa in 1888.