Doom Bar, a sandbar in Cornwall, was created by the dying curse of a mermaid. It doesn’t get much more negative-fantasyland than that!
I’m surprised we’ve overlooked Tombstone, Arizona for so long.
Spirit Lake, Washington, near Mt. Saint Helen’s. There are other Spirit Lakes in Idaho and Iowa.
The Valley of Ten Thousand Smokes, Alaska.
Mount Cerberus, Antarctica, named for the three-headed dog who guarded the entrance to Hades. There’s another Mt. Cerberus in Alaska.
Mount Satan, British Columbia.
You know, I’ve drunk many bottles of Doom Bar cornish ale, and never once considered what it was named after.
The Teufelsberg (Devil’s Mountain), in Berlin. It’s actually a recent name, for an artificial hill made from the rubble of the city after World War II.
Lake Vostok is a subglacial lake that sounds Russian, even though it’s nowhere near Russia. 
Although Russia claims it and has a station there. But it is weird: it’s technically a lake, but the surface is 4000 meters below the ice! Even if you didn’t mind the cold, it’d be hard to swim in there.
The name’s not fantasylandish, but the nearby Pole of Cold is.
Sounds like a D&D spell/dragon breath effect. They have “cone of cold” and maybe/theoretically “line of cold.”
Whoa what a thread. How have I only just come across it.
I need to add just about every place name in Stewart Island New Zealand. There is
Ruggedy Range
Gog and Magog
and heaps more. I don’t have a map immediately at hand, but visiting the island I felt that I was looking at a pirate map.
Man, that’s a freaky one! First, Nazis: it was built of the rubble of destroyed Berlin as people cleared and rebuilt West Berlin. Okay, not so unusual for war-torn Europe… But it was piled on top of the never-completed Nazi military university, which the Allies were unable to destroy. And then, the NSA built a spy station on top of it. Which was abandoned and is now itself in ruins.
And did I mention that is 80 metres high? Thirty or forty storeys?
Prime story fodder right there. We should get a couple of SCPs out of it at least…
Here’s a bunch from the mountains of Washington State:
Dragontail Peak
Forbidden Peak
Fortress Mountain
Storm King Mountain
Enchantment Peak
Dark Peak
Hoodoo Peak
Sinister Peak
Big Snagtooth
Mount Formidable
Mount Fury
Mount Terror
Mount Torment
Mount Despair
Mad Eagle Peak
Devils Peak
Big Devil Peak
Seance Peak
Cutthroat Peak
Devils Tongue
Phantom Peak
Tombstone Peak
Damnation Gully
What about the Rub’ al-Khali, the “Empty Quarter” of the Middle East? It’s always seemed the most desolate, fantasy-like name of all.
There’s a Storm King in New York too, on the Hudson opposite Breakneck Ridge.
Thunder Bay, Ontario.
Lightning Ridge, New South Wales.
The Hailstone River, Arkansas.
Deluge Lake, Colorado.
Tornado Alley, United States.
Post #25.
Ah, dammit, I missed that. I searched the page for “Rub” but didn’t search for “Empty”. Do I get half a point for linking it by its Arabic name rather than the English translation? 
I worked on Stewart for a bit. You’re right:
Halfmoon Bay
Deceit Peaks
Tin Range
Port Pegasus
Doughboy Bay
Muttonbird Islands
Big Moggy and Little Moggy Islands (a moggy being a housecat)
South Red Heat Point
Flour Cask Bay
Port Adventure
Adventure Hill
Breaksea Islands
Big Glory Bay
Pearl Island
Smith’s Lookout
City of Industry, California always struck me as reminiscent of paint-by-numbers 80s style sci-fi (or perhaps some semi-self contained comic book city like a Metropolis or Gotham but for a second-tier hero)
Twentynine Palms also seems kind of lazy fantasy writer to me…
The “Island In The Sky” district of Canyonlands National Park.
Bab al-Mandab (English: Gate of Grief) the strait connecting the Red Sea and the Indian Ocean.
Deception Pass strait in Puget Sound near Whidbey Island.
Booger Hollow.
Skid Row.
Holetown, in Barbados, doesn’t sound very nice.
It’s fictional, but I’ll mention “Tasty Meadows” from the film “The Incredible Shrinking Woman.” I suppose a lot of people will not appreciate the negative aspect it conveys.
There’s a mountain pass in southern Spain called “Despeñaperros.” There are a couple of theories as to the origin of the name, but it could be literally translated as “the place where people go to throw dogs off of a cliff” (the English-language version of the Wikipedia entry mistakenly translates it as “dogs plunging (over the cliff).”
Porte des Morts or Death’s Door, a strait at the northern tip of Wisconsin’s Door County peninsula with a dark history ranging from Native American conflicts to shipwrecks. The county’s name also came from the strait.