Long ago in the 1960s I read a story in a science fiction magazine that was not very much science fiction, if at all.
It was justified as sort of a "lost world" story set about 25 miles from New York City among a reclusive mixed blood group, known as the "Jackson whites" or Ramapough Mountain Indians.
It seemed like a perfectly realistic and naturalistic story to me except that I didn't know how accurately the group was depicted.
It was definitely what could be called a "genre bending" story.
I have come to suspect that it might be "The Devil Came to Our Valley", by Fulton T. Grant, Blue Book Magazine Volume 64, # 5, March 1937, Fantastic Stories of Imagination, volume 13, number 4, April 1964.
I remember reading two of the other stories listed in that issue of Fantastic and there is an introduction by Sam Moskowitz to "The Devil Came to Our Valley".