- Deputy Weld: "Welcome to Megaton. The bomb is perfectly safe. We promise."
Megaton is one of the more stable settlements around, with about thirty people, a sheriff, a water purifier, scavenging teams, and a wall to keep Raiders out. However, there is the little problem of an unexploded atomic bomb in the middle of the town, but hey, it keeps those nuts at the Church of the Children of Atom occupied, so how bad can it be? When the Lone Wanderer arrives, Megaton's fate can be decided. However, both New Vegas and 4 reveal that that canonically, Megaton survived the events of Fallout 3 and has greatly expanded in influence as both one of the most populous cities in the Capital Wasteland and the origin of the Wasteland Survival Guide.
Sheriff Lucas Simms
The de-facto Sheriff (and mayor) of Megaton, and likely the first person the Lone Wanderer meets on the surface. He's loved by the people and is reasonable and fair, but he protects the town with great ferocity and will not hesitate to pull his gun on anyone who threatens the peace.
- Asskicking Equals Authority: The reason he is officially in charge and Moriarty isn't? Simms has the better gun and more skill with it.
- Badass Longcoat: According to the game guide, he's a member of the Regulators.
- Bald, Black Leader Guy: Though you wouldn't know he was bald, unless he's killed and you take his hat off.
- Cowboy Cop: Subverted. While he does dress up as a cowboy, he's much closer to a By-the-Book Cop. For example he knows Burke is up to no good in town, but until he actually does something besides look and act suspicious he won't take action.
- Cutting Off the Branches / Killed Off for Real: The "Afterword" epilogue included only in the first edition of the Fallout 3 Official Game Guide Collector's Edition'' mentions, twenty years later, Sheriff Simms thinks the Lone Wanderer killed his dad when he actually saved the town. This implies that Burke's assassination attempt succeeded when the player turned him in. However, the entry was removed in later editions, making its canonicity questionable.
- Establishing Character Moment: Politely welcoming you to Megaton and giving you the lay of the land, before warning you that if you harm anyone, he will not hesitate to end you.
- I Owe You My Life: You can save his life when he stupidly turns his back on Mr. Burke after arresting him if you're quick enough. He thanks you for it, but he doesn't give you any tangible reward.
- Klingon Promotion: The title of sheriff seems to go to whoever puts on Lucas' duster after he dies. However, his prepubescent son Harden lays claim on the official duties of sheriff if his dad is murdered, and will refuse to recognize you if you put on his dad's outfit.
- More Dakka: His weapon with which to fend off the raiders is a Chinese Assault Rifle.
- Nice Hat: There's only one other like it in the Capital Wasteland (worn by Sonora Cruz of the Regulators). Which makes sense, since he is (or was) a Regulator himself.
- Reasonable Authority Figure: He's a nice guy with good morals and firm patience. You could make fun of him all you like, and insult his town, and he merely shakes his head and warns you to behave.
- Too Dumb to Live: If you ask him to arrest Burke, he runs to Burke and tells Burke to follow him. He then turns his back on him and puts away his rifle, leaving him open to a gunshot to the back. He even Lampshades it if you save his life.
- Ultimate Authority Mayor: He is both mayor and sheriff, which also seems to entail being judge, jury, executioner, and welcome committee. That being said, he's also a Reasonable Authority Figure who insists on seeing evidence of wrongdoing and won't shoot somebody just because they rub him the wrong way.
- "How the hell did you get up here, anyway?"
A sniper who keeps watch over Megaton from his vantage point over the front gate. That's about all there is to him.
- Badasses Wear Bandanas: He probably has it to keep his hair out of his eyes.
- Cold Sniper: He normally isn't even accessible to the player character due to his location. If the Lone Wanderer ever manages to reach him he'll tell them to leave him alone so that he can watch for raiders.
- Flat Character: He's just a fairly generic town guard with a name and some dialogue. Normally, it isn't even possible to reach him due to him being stationed above Megaton's front gate.
The owner of Moriarty's Saloon. Moriarity came to the Capital Wasteland from Ireland with his father as a child, and has been cooking up schemes ever since. He's got a lot of connections, and has a lot of people who owe him a lot of money. Lucas Simms may be the mayor of Megaton, but Moriarty is the one aiming to have complete control over the citizens.
- 0% Approval Rating: Everyone wants Moriarty gone. And he knows it.
- That said, they will still open fire on a Lone Wanderer who gets caught killing them.
- Can't Kill You, Still Need You: He claims to be descended from some of the original settlers of Megaton, and whether this is true or not, he's amassed enough wealth and connections over the decades that he's vital to the town's economy. It's heavily implied that the townsfolk would have gladly kicked him out years ago if this weren't the case.
- Evil Cannot Comprehend Good: He's convinced that Billy killed Maggie's parents and uses her as a slave. No evidence can be found to back this up, suggesting Moriarty simply can't understand Billy's altruism.
- Faux Affably Evil: He'll act all polite and friendly to your face, but one look at his computer tells us what he's saying about people behind their backs...
- For the Evulz: There's a rumor in town that Moriarty pisses in his drink stills, just because he can.
- Hate Sink: One of the more despicable characters in the game overall thanks to his infamous Jerkassery. Many a player will go out their way to kill him secretly ignoring the karma penalty.
- I Own This Town: His connections, information and general power would allow him to take over Megaton if Lucas Simms wasn't around.
- Jerkass: Keeps information on his terminal to blackmail people with, overcharges on alcohol, and refuses to tell the Lone Wanderer about his father until paid. However, despite being a complete bastard, technically he's not evil, just really manipulative. Because of this, you lose karma for killing him, even if everyone in Megaton would be thankful for him to be gone.
- Knowledge Broker: He keeps tracks of anyone walking through Megaton, and frequently spies on his fellow citizens in the hopes of getting blackmail material. It is somewhat downplayed in that he is not terribly concerned with what happens outside of Megaton, and therefore his knowledge of that tropic is quite limited.
- Mean Boss: Treats his workers like shit, putting them in so much debt to him that they are essentially slaves. He forces Nova into prostitution, and he regularly beats Gob viciously. When Silver tried to get away from him, he sends you out to kill her.
- Morality Pet: Shows genuine affection towards Nova, letting her demand free time off and letting her mouth off at him. Then again, it's implied that he takes advantage of her services whenever he likes, without paying her for them.
- Moving the Goalposts: This is how he keeps Gob working for him. Every time Gob makes any progress towards paying off his debt it is quickly undone by Moriarty charging him for trivial things and piling on more and more costs for him to pay back.
- Mysterious Past: His actual origins are difficult to pin down. If you ask him, he'll tell you that his ancestors founded Megaton all the way back when the bombs dropped, but more credible accounts suggest he came over from the British Isles with his father as a child.
- Pet the Dog: Ordinarily, Moriarty would've have thrown James and his child out of his establishment when they met for the very first time, simply because said child's crying annoyed him, but James talked him out of it. In fact, if you read Moriarty's notes, you get the feeling James actually managed the rare feat of getting actual courtesy and respect out of Moriarty. And, in a smaller instance, he does wind up leveling with you and telling you the mostly unvarnished truth even if you fail the speech check. That said, bear in mind this man is a known liar.
- He also offers a toast to James after he dies.
- Tempting Fate: He says on his terminal that he doesn't care if Burke stays in town until the atomic bomb explodes so long as he always pays for his drinks. Guess what happens if the Lone Wanderer rigs the bomb with Burke's detonator.
An unfortunate ghoul who came to Megaton from Underworld seeking adventure. He ended up as Moriarty's worker (basically a slave) to pay off a debt he owed, which Moriarty unfairly increases by charging him for trivial things like simply living there.
- All Love Is Unrequited: Is in love with Nova but she seems to regard him as a friend.
- Because You Were Nice to Me: His reason for risking Moriarty's wrath by giving the Lone Wanderer a discount? The Wanderer was the only customer who didn't insult or hit him.
- Hopeless Suitor: To Nova
- Indentured Servitude: Moriarty has him trapped as a indebted slave and is always finding new ways to add to his debt to keep him working and preventing him from leaving.
- Nice Guy: He's meek and friendly, once you demonstrate you won't abuse him.
- Under New Management: If you kill Moriarty, Gob will eventually take over the saloon, making it Gob's Saloon. He's likely much happier after this.
The town prostitute. Working for Moriarty (under duress), she clearly hates the guy like everyone else in town, but otherwise is rather decently regarded by everyone else.
- Bi the Way: Can sleep with the Lone Wanderer regardless of gender.
- Hooker with a Heart of Gold: She is rather affable and pleasant to everyone, but what makes her more than just a nice girl is that she can look past the fact Gob is a ghoul and she treats him like a person.
- Ms. Fanservice: Easily the sexiest woman in Megaton without trying very hard.
- Under New Management: If you kill Moriarty, Nova will take over running the inn part of the saloon, and will no longer be a prostitute.
The owner of the Craterside Supply, the general store in Megaton. She's weird. The Lone Wanderer can help her fulfill her life's dream of authoring the definitive book on how to survive the wasteland. Conversely, the Wanderer can rip her off, hiding out in the saloon all day, then coming back to give her idiotic and dangerous advice.
- Adorkable: Her incredibly chipper demeanor and enthusiasm with her research makes her this.
- American Accents: She has a very distinctive Upper Midwest accent, which helps with her general personality.
- Big Good: Despite her oddities and foibles, her driving motivation behind her actions is to become one of these for the entire Wasteland, courtesy of publishing the definitive guide on how to survive in a post apocalyptic world, and seeing how the guide has gotten as far as the Mojave Wasteland in just four years and boosts the Courier's survival skills, it seems that the Lone Wanderer canonically helped her extensively in her research.
- Cloud Cuckoolander: Her enthusiasm for "science" and Pollyanna tendencies paint her as one. For example, there's her mistaken belief that the Capital Wasteland Mirelurks have an advanced underwater civilization.
- Cutting Off the Branches: New Vegas and 4 confirm that she was largely successful with the Wasteland Survival Guide, as it's available in both games as a Skill/Perk Book.
- For Science!: When the Lone Wanderer (frequently) calls her out on how dangerous her requests are, she'll insist that they're for the good of science, and therefore humanity as a whole. Her requests involving radiation and crippling injury specifically invoke this response if you try and protest.
- Genki Girl: She's always smiling and cheerful. Even if she ends up Ghoulified if you choose to nuke Megaton. Hell, she probably found her newfound resistance to extreme radiation to be be fascinating!
- Hidden Depths: If you ask her what she could possibly hope to accomplish by writing the Guide, she gives a surprisingly passionate speech about "a piece of broken glass": even if a broken glass bottle can't be repaired, you can still put the shards back together to make something useful. Well, the world got "broke" in the Great War, and it's time to try to put it back together.
- Literal-Minded: Hand-in-hand with Sarcasm-Blind. Some of her notes are straightforward in a way that could be taken as a joke ("What do Super-Mutants eat?" / "Research assistants"), except Moira seems to mean them seriously.
- Mad Scientist: A lighthearted and humorous take on the trope. Moira is genuinely trying to improve the wasteland, but her "experiments" reach into this trope. Her terminal entries, for instance, include wondering if Brahmin heads learn independently, if Centaurs can talk, if explosives can be used to expand the town, and if Mole Rats can be domesticated (which actually is Hilarious in Hindsight considering how in New Vegas, the Mole Rat "Snuffles" is the town pet of the NCR mining town Sloan). There's also this quote after the radiation part of the guide quest:"Well, you're alive... That's the good news. But there was a little side effect. A teeny, tiny, um, mutation. But it seems to be benign, at least. Here, take a few radiation Chems, as my little way of saying, "I'm sorry I twisted your DNA like a kitten with a ball of yarn."
- Mentor Ship: She and the Lone Wanderer are probably the most frequently shipped couple in Fallout 3.
- Nice Girl: Her quirks aside, she really does have no ulterior motives aside from wanting to help people with what she discovers from her experiments.
- Try Not to Die: She'll send you off on incredibly dangerous missions with friendly advice to this effect - especially the ones where you need to become injured and have a broken limb. She will even cheerily say the trope name word-for-word.
- The Pollyanna: Especially obvious if you nuke Megaton. She will be turned into a ghoul, but won't care at all, and even thanks you for detonating the bomb because she thinks its nice that "you helped those nice people at the Children of Atom out".
- Sarcasm-Blind: Moria has a bit of difficulty understanding some of the sarcastic responses for her quest.
- Sink-or-Swim Mentor: She somewhat mixes this with Big Sister Mentor toward the Lone Wanderer (if her quest is accepted early in the game) as she has them go through several potentially fatal scenarios expecting them to come back so she can hear what they've learned, though Moira does try to sweeten the deal by paying the Lone Wanderer for every task they accomplish and sure enough, if they complete every task (including the optional parts) properly, the Lone Wanderer will have grown into a genuine Wasteland survival expert.
- Voiced by: Shari Elliker
One of the owners of The Brass Lantern and Moriarty's only business competitor.
- Big, Screwed-Up Family: Andy is incredibly angry and bitter, even chatting with Burke about his little deal, and Leo is a notorious addict. She seems to be the only one with a level head.
- Doesn't Like Guns: It appears that way, she carries a .32 pistol, but never uses it, even when attacked.
- Stepford Smiler: You'd never know from talking to her, but Jericho tried to rape her a while back. At night while she's sleeping you can hear her talk in her sleep while having nightmares.
An old (and possibly senile or insane) man who spends his entire day standing in a puddle of irradiated water next to an undetonated atomic bomb. He preaches about the "Children Of Atom", a bizarre religion that believes individual atoms contain entire universes, and thus nuclear destruction is not destruction, but a ritualistic purification and creation of new existences.
- Cloud Cuckoo Lander: He worships an undetonated atomic bomb and sees a nuclear holocaust as a good thing. Standing knee-deep in radioactive water all day may or may not have something to do with that...
- From Nobody to Nightmare: He's just a nutty preacher spouting nonsense about radiation in Fallout 3. Come Fallout 4, and he now leads a massive(ly violent) congregation, and is now regarded as a prophet by his followers. He even has the influence to send his followers as far north as Maine.
- Good Shepherd: Whether his message is a good thing to believe in or not aside, he's pleasant enough to the Lone Wanderer if spoken to, and judging by the fact he and his parishioners helped build Megaton, his teachings seem to encourage reaching a helping hand out to others as long as you respect their beliefs.
- Hypocrite: He says that all Children of Atom must be sober pacifists, but you can find a pistol and whiskey in his office.
- Reality Ensues: Due to what could be a bug, you can occasionally enter town and find him lying dead in the pool from radiation poisoning. Well, what do you think will happen to an old man who spends all day ankle-deep in a pool of water around an old nuclear warhead?
A trader who helps Megaton stay supplied. Raises a little girl named Maggie orphaned after a Raider attack.
- Abusive Parents: Subverted. Colin Moriarty believes that he killed her parents and is raising Maggie for unsavory purposes, but examination of his home and Maggie's current well being rather easily prove otherwise.
- Badasses Wear Bandanas: He is one of the stronger residents of Megaton and will have no problem fighting back if attacked.
- Dark Is Not Evil. He looks like your typical wasteland rent-a-thug with his bandana, eyepatch, goatee and merc clothes but is actually one of the friendlier Megaton residents. Just don't piss him off.
- Eye Scream: Apparently suffered one in the past, judging from the eye patch.
- Good Parents: He downplays this, but it's obvious Maggie is doing well under his care.
- Promotion to Parent: Self-induced after taking her in after a Raider attack. He even lampshades that if wasn't what he intended, but if he had his own daughter, he'd want her to be like Maggie.
- Totally Radical: His speech is peppered with "hip" expressions.
A cranky old man who serves as Megaton's best (and only) doctor. Most players have a strong love/hate relationship with him, they hate his guts and annoying comments but love his stimpaks and medicine. The fact that he is one of the only easily accessible medics for the early parts of the game is a good enough reason to keep him around, otherwise he'd likely end up face down in the irradiated water surrounding Megaton's warhead next to Cromwell after his first introduction.
- Dr. Jerk: His defining characteristic. If the player ever needed a good excuse to blast Megaton back to the stone age he is it. Not helped at all by his annoyingly repetitive comments about you pestering him."For christ's sake, you don't look sick and you sure as hell don't look dead, so why are you bothering me?""All better now, you big baby. Can I get back to work now?""Try not to hurt yourself.""You don't got nearly enough holes in you to be botherin' me."
- Jerk with a Heart of Gold: As rude as he is with the player he actually seems to care about the people in town and tries to be as professional as possible with them. He'll also show genuine concern if the player is critically injured when they visit him. (He'll still charge you through the nose for a fix up though.)
- Retired Monster: Similar to Flak in Rivet City he used to work for the slavers in Paradise Falls, though to what extent he supported them and how far his help actually went remains vague.