I posted this in the Alsace message board, but thought I'd try here as well.
This may be a bit of a hopeless cause, but nothing ventured nothing gained.
My great-great grandfather, George Ahart was PROBABLY born in Alsace and PROBABLY named Georg Ehrhardt (or some variation of that last name) My other 3 great-great grandparents are all definitely from Alsace, and everyone settled in an area known as Germany Hill in Tioga County, New York (there seems to have been quite a large number of immigrants from Alsace in that area)
Here's the information I have about George Ahart:
1850 Census Geo Airhert age 45 (abt 1805 in Germany - I think the age is a misprint or misunderstanding) Tioga, Tioga, New York
1860 Census George Ahart age 42 (abt 1818 in France) Tioga, Tioga, New York
1865 NY Census George Ahart age 47 (abt 1818 in France) Tioga, Tioga, New York
1870 Census Geo Ahart age 52 (abt 1818 in France) Tioga, Tioga, New York
1875 NY Census George Ahart age 58 (abt 1817 in France) Tioga, Tioga, New York
1880 Census George Ahart age 62 (abt 1818 in France) Tioga, Tioga, New York
Other possible info:
8 Aug 1828 passenger list for "Samuel Robertson" lists a George Air Hart age 14 (abt 1814) traveling with Fredrick Air Hart, age 45 (abt 1743) a butcher - no sign of either of them in the 1830 or 1840 census that I can find, but Fredrick might not have been head of household.
25 Dec 1817 The birth registry for Ottwiller, Bas-Rhin, Alsace, France (Ottwiller, N, 1817, 4 E 369/1) lists a Johann Georg Ehrhard. Parents Johannes Ehrhard age 64 and Anna Barbara Motsch age 24. Johannes died in 1833, but Barbara Motsch shows up in the 1836 Census with her 3 other children, but no sign of Georg in Ottwiller. I've looked for a death notice for Georg in Ottwiller, but haven't found it, so he's still a possibility. I have not been able to find a Friedrich born around 1743 in Ottwiller to connect to the people on the "Samuel Robertson".
Other birth registries (1807-1819) consulted include: Altwiller, Bouxwiller, Diemeringen, Harskirchen, Ingwiller, La Petite-Pierre, Lohr, Neuwiller-lès-Saverne, Niedermodern, Oermingen, Ottwiller, Petersbach, Sarre-Union, Stasbourg, Wolfskirchen
I'm at a bit of a loss, so any help or suggestions would be greatly appreciated.