My Woelfel/Kerfin family has Neyendorfs buried in their plot in Concordia Cemetery near River Forest, Illinois. My sister got the information from the cemetery and, at the time, there was some confusion about whether the name was Neyendorf or Meyendorf, because of the spelling on the gravestones or the records. (We are not even sure if the Neyendorfs there are blood relatives of ours.)
Meyendorf, Meyendorff, and von Meyendorff are/were family names in the US, Germany, Estonia, Russia, etc.
Like Don says, there are many versions of Neuendorf. And in Germany there is also Neiendorf.