In the 1930s, Otto G. Lindberg, Ernest Alpers, were tasked with drafting a New York state map. They plotted the fictional town of Agloe, which is an anagram of their initials, between Beaverkill and Rockland.
It was created as "trap" or "paper town," as a type of copyright protection.
Argleton, also a town that doesn't exist is mapped on this site (link below). It is no longer shown on GM imagery.
Links: virtualglobetrotting.com, en.wikipedia.org