Seminal American horror author H.P. Lovecraft lived in New England and set much of his anthology in the decrepit, misty alleys and hills of that part of the world, recently-civilized enough (on a global scale) to still have hints of the unknown just out of view in the periphery of the morning fog, yet venerable enough (in terms of North American colonies) for people to have still had enough opportunity to leave many boxes unclosed.

Lovecraft fans have long speculated on the particular cities, towns and hamlets which were the inspirations for the fabricated settlements wherein many of the stories in his Cthulhu mythos were set. The alt.cthulhu.horror FAQ suggests the following real-world analogues to some of his most (in)famous locales:

These proposals should be tempered with the realization that Lovecraft also made good use of real locations (the example given in the FAQ being that most of The Case of Charles Dexter Ward is set in Providence), but keep in mind that some of his tales describe quite grim goings-on with the full complicity of communities and towns might take it the wrong way were he to outright accuse them of being populated by the inbred miscegenations of humans and satanic fish-men 8).

There are vague locations asserted for other places alluded to in the stories but usually far from the action itself: the Plateau of Leng was suggested by Lovecraft himself in three different works (The Dream-Quest of Unknown Kadath, At the Mountains of Madness and The Hound, respectively) to exist in the far north of Earth's Dreamlands, near the South Geomagnetic Pole in Antarctica and high in the Himalayas, possibly simultaneously in all three locations (and more?) due to the effects of the Great Old Ones on space-time. The last of those three is the one which has been most utilized by Lovecraftian writers since, and Tierney went so far as to say in "House of the Toad" that the Plateau of Leng was located in China's Xinjiang province.