New Pork City is the largest city in Mother 3, and is also where the game's last chapter takes place. It's based on New York City very closely, Also note how polluted it is.
New Pork City is the base of Porky, the leader of the Pigmask Army. It is also the largest city in the game, as well as the most expensive. There are numerous vendors that sell expensive, but useful items. This city is known to eat your money. Then again, with this being the final part in the game, you can't really blame it.
New Pork City is the location with the most references to the other Mother games. For example, in the theater, there is a movie playing with clips of the adventure players followed in Earthbound. The clerks also sell Fake but useable items from EarthBound, Like Ness' Hat and Bat and Paula's Ribbons and Fry pan. Another reference is the music played in the higher floors of the Empire Porky Building plays songs such as Pollyanna. There are also some characters that resemble Earthbound characters, such as a robot maid that looks like Porky's mother, and the Sanchez Brothers. Also, in one of, if not, the highest room in the game, there is also a boat that passes by objects from Earthbound, such as the Phase Distorter, a giant iron pencil, and the Twoson-Threed bus.
New Pork City also holds the strongest enemies in the game: The Ultimate Chimera, the King Statue, and the NK Cyborg. Beneath New Pork City lies Porky, the Masked Man, ready to pull the last needle, the last needle itself, and the Dark Dragon.
It also holds the strongest items in the game, Like the New Year's Eve Bomb, Which is one of the only two weapons that can defeat the King Statue.
Once you enter New Pork City, you can't leave. This is the final point in the game, and it is impossible to go anywhere else.