Eixendorf (by Neunburg vorm Wald) in Kreis Schwandorf, Bavaria, Germany, was the home village of the Alt family before 1839. The descendants of this Alt family lived in the Plain, Wisconsin area.
Eixendorf was a very small village of a handful of homes and farms located about 1 hour northeast of Regensburg, between Neunburg vorm Wald and Rötz. If you go to Eixendorf, you'll see only water. From 1972 to 1975, all the villagers of Eixendorf and possibly a couple of other small villages had to leave their homes and farms because of the planned "Eixendorfer Staussee" (a reservoir bridge, dam, and new highway #2151) that was built over the Schwarzach river. Eixendorf was on the north side of the Schwarzach river. The land was flooded over to make the new lake. To the east is Stockarn.
Look at the historic map from BayernAtlas (dated from 1817 to 1841 or 1860s):
https://geoportal.bayern.de/bayernatlas/?lang=de&topic=ba&catalogNodes=11&bgLayer=historisch&E=750084&N=5471681&zoom=13&crosshair=marker
Eixendorf church records are online in the parish of Neunburg vorm Wald:
https://data.matricula-online.eu/en/deutschland/regensburg/neunburg-v-wald/
For travel info and sights to see, go to this page