When it comes to the lore of Fallout, there are areas that are pretty much hell on earth. These areas are nightmares incarnate. So my question for my fellow GUNers is, what are the most dangerous areas in Fallout lore-wise?

My personal answers would have to be Dog City Denver, the Glowing Sea, and the main setting of Fallout 3—The Capital Wasteland.

Dog City is pretty much a goldmine for valuable loot and resources, but the area is basically the Devil’s butthole. The sandstorms are said to literally burn anything it comes in contact with, there are huge climbing lizards, mutant bats, cockroaches(or “rad”) that can reach the size of of fucking tiger, and oh yeah, infected dogs. The only people inhabiting the area are Legion slavers and prisoners who were sent by the NCR to salvage resources. The humans staying there have to shack up in skyscrapers or heavily fortified buildings to stay alive. Other than that, DCD is a great example of an area that has been taken over by the wild.

The Glowing Sea in Fallout 4 is the most highly irradiated region in the Commonwealth. It was ground zero for the high-yield blast that devastated most of Massachusetts. The area is filled with radiation and all sorts of abominations. It also holds some of the most interesting landmarks in the game. The only people that inhabit the region are the Children of Atom—and well, you know how they are.

The Capital Wasteland in Fallout 3 is a fucking hellhole. Yes, people have been able to form civilizations there, but those place are few and far in between. Most of The Capital Wasteland  is filled psychotic raiders who will kill you, or worse. There supermutants that will eat you for dinner or turn you into one of them. There are slavers who will capture you when you least notice it and sell you off to the highest bidder. Then there are the multiple abominations that will rip you apart and feed you to their little babies. Washington, D.C. is a war zone, like Lucas Simms said. You have raiders fighting supermutants who are fighting BoS. You have the metro tunnels that inhabit God knows what. The only safe haven in D.C is Rivet City and the Citadel.

LA vault aka Master's Base. No other place in Fallout has walls of living human flesh, leading to a nightmarish puddle of someone who once was a person.

Divide. Winds so strong they tear the skin off your flesh and drive you insane.

Point Lookout. If the tribals don't kill you, there's always the mutated swampfolk that will chase you down and eat you. The place is pretty freaky, atmospheric and it oozes desolation. 

The Sierra Madre is pretty dangerous too, especially if you're one of the Courier's crew. One member goes running into a room full of radios or gets killed by ghost people, and the rest of the crew is as good as dead. The whole place is like one big labyrinth of destroyed buildings. 

Far Harbor is very similar to Point Lookout, so it could also be considered more or less dangerous than it.

Pittsburgh's a pretty dangerous place I think. Not only is it controlled entirely by raiders - one of whom is a former Brotherhood of Steel Paladin - but there's feral mutants beyond the city along with rampant diseases and toxic pollution that turn people into said mutants.

The Glow deserves a mention as well. Other than radiation there isn't much danger, but the place is quite eerie to explore especially with Mark Morgan's OST in the background. Not even the BoS wanted to go down there. And the worst part? Forgetting to take a rope with you.

And last but not least, Big Mountain. Crazy robot scientists who've completely lost their minds run brutal experiments on anything and everything around them, just for the heck of it. Lobotomites, spliced animal subjects, killer robots, facilities that are almost alive in the sense they're run by AIs whose programming either decayed, or have just always been out of wack.

Vault 87's Surface entrance. Just the 3000+ RAD a sec alone is enough to call it extremely dangerous.

Cazador nest because I hate Cazadors . FONV has a few areas the Fort and the divide but FO3 every other location you find has a sense of dread and danger from big areas like D.C its self to the smaller areas like Andale a nice peaceful place that tricks wastelanders into feeling safe only to get slaughtered and eaten

Surprised nobody's mentioned Dead Wind Cavern.

I recall the Adytum Boneyard being pretty deadly as well. Deathclaws, raiders, the Regulators, gangs, the Children of the Cathedral and Nightkin.

The Glow from Fo1. I ended up getting stuck there and had to start the whole game over lmao.

Quarry Junction, i went there for the first time at level 4 and felt like if Satan just grabbed my ass lol

The Mojave Dessert generally doesn't seem to be the most safe place for ordinary citizens. It always bothered me how easy you as the courier can get from place to place when every random npc you meet fears of being killed by the Powder Gangers, Legion, Jackals gang or the Khans.

And of course Quarry Junction and Old Olney don't seem the most fun places.
If you didn't own all the dlc's for Fallout 3 it would be impossible to clear Old Olney with level 20 and a normal gatling laser.

Deathclaw Promontory in FNV. Not the best place to picnic...

As far as anyone can tell, China.

When we see it during mothership Zeta it's just a glowing crater on the globe. I can only imagine what the hell the reality of something like that is. I'm gonna guess glowing sea x1000.

Other obvious choice that have been said are the masters vault, the divide, or any of the major fallout animal nests but honestly, let's not forget the society created by the post war era namely the pitt. It's easily one of the most horrific places in fallout. A slave city ran by raiders, where slaves are fed the flesh of infected humans, whilst succumbing to the infection themselves and either becoming wildmen or trogs. The only way out is to fight in the arena to the death, which few people could do outside of an overpowered pc. Slaves can be seen thrown from scaffolding, dying in stocks, executed by raiders or sent to die working in the steelyards. It's an impossible situation for nearly anyone who finds themselves in it. So yeah, the Pitt slaves have one of the worst lots in Fallout.

I believe it's already been said but definitely the Sierra Madre. It's said in an alternate ending that Elijah killed everyone in the Mojave in a few short years after unleashing the gas of the Sierra Madre.. Bad stuff