This version, which comes from a namesake in the U.S., refers to the close vicinity of our South Pfalz to the neighbour country of France and assumes, that there is a French root in our Name:In the past, there were people (soldiers or armed guards), who stood watch at the town portals - in German: am EINGANG.
Perhaps these people had been called as in German: Der am EINGANG (He at the entrance).
Because of the closeness to France, perhaps there has been an amalgamation of languages, i.e. the French article ” Le ” , and together spoken it had been to
” L’EINGANG ” .
(If I can find a picture to this version, I will insert it here)
My Opinion to this version:
Earlier generations spoke a much French, because the Pfalz had been once part of France during its history. However, all French words spoken in the Pfalz got eventually a German article in front (for example: die Chaiselongue, der Parapluis etc). I think, that ” Der am Eingang ” with a French root would have to be had called in German ” der Entree ” , mixing the German article and the French word.
Because of this, I believe that this version is a bit improbable, but who knows for sure?