One quick FYI: the OP links to the Agloe's entry in the U.S. Geographic Names Information System database. The database is available as a bulk download here:
It's a fairly large (2.2M rows) and handy data file that can be used to extract geo-coordinates and metadata for U.S. geographical features, i.e. cities, states, counties, parks, even cemeteries, in lieu of hitting up a geocoder.
The modern Village of Sleepy Hollow only got its name in 1996 - before then it was called North Tarrytown. But it is certainly the place that Washington Irving was writing about and the Old Dutch Church still stands there.
...In that Empire, the Art of Cartography attained such Perfection that the map of a single Province occupied the entirety of a City, and the map of the Empire, the entirety of a Province. In time, those Unconscionable Maps no longer satisfied, and the Cartographers Guilds struck a Map of the Empire whose size was that of the Empire, and which coincided point for point with it. The following Generations, who were not so fond of the Study of Cartography as their Forebears had been, saw that that vast map was Useless, and not without some Pitilessness was it, that they delivered it up to the Inclemencies of Sun and Winters. In the Deserts of the West, still today, there are Tattered Ruins of that Map, inhabited by Animals and Beggars; in all the Land there is no other Relic of the Disciplines of Geography.
"In Alexandria Drafting Co. v. Andrew H. Amsterdam dba Franklin Maps,[6] the court ruled that "fictitious names may not be copyrighted" and "the existence, or non-existence, of a road is a non-copyrightable fact".[7]"
It is a nice reminder that the things we think of as "official" were once made up by someone. Indeed, that is all language and culture is! We just happen to agree upon them.