Outlaw Town

A Sub-Trope of Wretched Hive, an Outlaw Town is a town (or other settlement) run specifically for the benefit of criminals on the run. It gives them a place to lay low till the heat is off, and spend or store their ill-gotten gains.

Typically the people running the town will demand a portion of the criminal's loot in return for offering safe haven. Paradoxically, these settlements are often not lawless, as the people running the town will crack down hard on behaviour that might attract the attention of outside authorities.

An Outlaw Town differs from a normal city with high levels of corruption in that the Outlaw Town is entirely run by criminals and all of its inhabitants are criminals. Unlike a corrupt city, there will be no honest citizens sick of the corruption, no honest cops battling the system. Any inhabitants who are not on the run themselves will be knowingly providing services and shelter to wanted criminals (which makes them criminals themselves) and any 'law' that exists will be the personal enforcers of the town's boss. Also Outlaw Towns will often not 'officially' exist on any map; being located in remote locales and their existence known only to the underworld.

Examples of Outlaw Town include:

Anime and Manga

Crash Town from Yu-Gi-Oh! 5D's may qualify as this.
Roanapur is an excellent example.

Comic Books

Jonah Hex found his father acting as sheriff of an outlaw town, called Outlaw Springs, in "Christmas in an Outlaw Town".
The Lucky Luke album Dalton City.
Batman encountered one in "Outlaw Town, U.S.A." in Batman #75.

Film

In the western comedy Cat Ballou, "Hole in the Wall".
In Pirates of the Caribbean III, "Shipwreck" - the city built out of pirate ships used as headquarters for the pirate council.
- Don't forget Dry Tortugas.

Literature

An outlaw town named Hell featured in two of J. T. Edson's western novels: Hell in the Palo Duro and Go Back to Hell.
A settlement dedicated to smuggling criminals and illicit goods in and out of the country features in the Doc Savage novel The Mountain Monster.
Lagrimas Negras in the Young Bond novel Hurricane Gold.
The Undertaker encounters an Outlaw Town in Canyon of Death, the third book of The Western series The Undertaker by George G. Gilman.
A subversion in the Honor Harrington books: Erewhon is a planet founded by an alliance of Mafia families hoping to set up shop outside the reach of any existing law enforcement agency. Over the centuries, they evolved into a planet that was still run by those families, and still carried with it many of the old traditions, but which also had some of the strictest law enforcement in the galaxy.
Dashiell Hammett liked this trope, using it in the short story "Nightmare Town" and later expanding it into Red Harvest.
Jackson's Whole in the Vorkosigan Saga was initially a hijacker's base and along the way became "governed" by a loose connection of crime families specializing in specific crimes (sex slavery, arms dealing, etc.). It is ultra-capitalist and has no real laws to speak of- a handshake is as good as a contract, and you are as good as dead if you aren't under the protection of one of its crime families.
Bab-el-Shaitan ("the Gate of the Devil") in the Robert E. Howard story "The Blood of Belshazzar".
Several of Andre Norton's space adventures mentioned a Thieves' Guild base known as Waystar. Eventually, one book revealed it to be a Space Station dating from before humans had star travel—and with a tightly-packed cluster of derelict ships put in place as an outer wall or camouflage, separate from the station itself.

Live Action TV

Roy and Pat pose as outlaws to infiltrate an outlaw town in The Roy Rogers Show episode "Outlaw's Town.
The Lone Ranger faces one in "Outlaw Town".
Star Trek: The Original Series had a Planet of Hats that purposefully based their culture on the Prohibition Era Chicago Mob.
The town of Twin Butte, in The Cisco Kid episode “Haven for Heavies”, was run by a sheriff that granted immunity to outlaws that settled there.

Theatre

The city of Mahagonny from Bertolt Brecht's The Rise and Fall of the City of Mahagonny. If not the Trope Codifier then one of the oldest and most well-known examples of this trope.

Video Games

Lawenilothehl in the roguelike Ancient Domains of Mystery is a town run by outlaws. Everyone in there is a bandit of some form.
In Dragon Quest VIII the town of Pickem is run and mostly inhabited by thieves and bandits.
Fable I has Twinblade's Camp. Fable II has Bloodstone. Fable III has the Mercenary Camp. (The camps may or may not count, depending—they play and operate just like the towns in the rest of the game, but no one ever refers to them as towns. Bloodstone is a straight example, however.)
The Den in Fallout 2.
The space station of Omega in Mass Effect 2.
Pokémon Colosseum has Pyrite Town.
Red Dead Redemption has Thieves' Landing, a bayou town with no law enforcement at all.
Sly 3: Band of Thieves has Blood Bath Bay, a town inhabited by the most stereotypical, anachronistic pirates you could imagine...and they're also Petting Zoo People.
StarCraft II features Deadman's Rock, an entire outlaw planet.
Evolution Worlds: Pine Village, Carcano's hideout, is just a big town over the water fully inhabited by thieves.

Web Comics

Gang Rule Town in A Path to Greater Good.

Western Animation

The Adventure Time episode "City of Thieves".
Blackwater asteroid in Adventures of the Galaxy Rangers. It was thought to be an Urban Legend by law enforcement until a delirious Cody Carson (a shady quasi-ally to the Rangers) proved it wasn't by all but kidnapping Doc and Niko and taking them there.