@ZachWeinersmith The only real one I can think of off the top of my head is "Bangor", which I know of in Maine, but there are apparently more of them.

That said, I have a totally unsupported hypothesis that it may have roots in Indian / middle eastern names, which cemented themselves as "foreign sounding" names for the English language sometime between the crusades and the era of the East India Company.

A quick look at Google Maps does appear to show many names ending in "<vowel>r" in those regions.