Bikini Bottom is the main setting in SpongeBob SquarePants.The city consists of various businesses, including restaurants, stores, and manufacturers. The city has a stable economy, a balanced education system, questionable health care (as seen in "The Lost Mattress") and labor laws, a structured government, and a firm law enforcement system. There are even stadiums, amusement parks, and other recreational facilities. Bikini Bottom first was mentioned in the episode: "Plankton!" but first appeared in the episode: "Help Wanted." Bikini Bottom is also home to all of the characters.
Bikini Bottom is located at the bottom of the sea, below its signature island, Bikini Atoll, according to Stephen Hillenburg. There are many instances of evidence of this in the show: After being scared off by "ghosts", Sandy Cheeks evacuated to Texas. She was seen flying east from the Pacific Ocean. In the Employee of the Month computer game, a fish mentions that Bikini Bottom is located in the Pacific Ocean. In The SpongeBob SquarePants Movie, when SpongeBob was singing the "Goofy Goober Rock", the camera rose out of the water into outer space. When it did, it came out of the Pacific Ocean. In the TV commercial "Plankton's Holiday Hits", Bikini Bottom is revealed to be part of the United States, and its residents Americans. Bikini Bottom is placed beneath its namesake island, Bikini Atoll, in the Pacific Ocean. Bikini Bottom's location at the bottom of the Pacific Ocean is mentioned or referred to in several different episodes, and in the movie, The SpongeBob SquarePants Movie. In the episode Hide and Then What Happens?, it is revealed that Bikini Bottom is located in an island with Jellyfish Fields and Goo Lagoon, surrounded by the goo seen in Goo Lagoon. In SpongeBob's Last Stand, Bikini Bottom is on the Outskirts of Nowhere. In multiple episodes, an explosion, which is actually the Baker bomb that was detonated in Bikini Atoll, occurs.
The city is divided by its main road, Conch Street, which runs from downtown, past the homes of SpongeBob, Squidward, and Patrick, through the Krusty Krab restaurant, The Chum Bucket and the Reefhouse cinema.
In every episode in which the skyline of Bikini Bottom is shown, features such as buildings, houses and an anchor can be seen. In earlier episodes of the series, a red flower arch can be seen, which no longer appears in the skyline. In some episodes, a lighthouse appears in the skyline, most likely Mrs. Puff's Boating School. Other episodes feature the Krusty Krab's Marquee. A large clam-shaped structure, most likely a propeller from a ship, is seen in some episodes.
In the center of Bikini Bottom, the citizens work and live in large, gray buildings made of metal. There are some other forms of buildings, mostly aquatic-themed as seen above. Further out from the town citizens need to use whatever is available and easy to live in, such as Patrick's rock, SpongeBob’s hollowed-out pineapple and the stone monument Squidward lives in.
Bikini Bottom seems to mostly be made up of scrap metal and whatever items may fall down from the surface. This seems to elude to the fact that undersea life is mostly scrap living wherein a stable sea-wide society has not yet, or may never be formed. The structures of the buildings in the main part of town have a relatively wavy structure, probably due to undersea currents. These buildings may be apartments. The homes that are made of different items from the surface may be a more residential or suburban area, possibly close to Goo Lagoon and Jellyfish Fields.
Although the population of Bikini Bottom is uncertain, Stephen Hillenburg, the creator of the show, confirmed that Bikini Bottom is a large city. Before almost leaving the city, Sandy Cheeks sang a song about the city, describing it as "crowded and smoggy," which are the characteristics of Los Angeles, although the physical look & feel of Bikini Bottom suggests that it is in fact a much smaller city. A one-time Pretty Patties joint created by SpongeBob attracted 46,853 customers. Almost everyone from the city is there, which may suggest a population of around 50,000 Bikini Bottomites. In the episode, "Squilliam Returns," Squidward mentions Bikini Bottom is a "hick town", meaning it is probably quite small like most hick towns. On "Krusty Towers", Squidward mentions Bikini Bottom is "in the middle of scenic nowhere", which could mean it is very small, which is the criteria of isolated cities. However, for both of the latter examples, one must take into account Squidward's negative personality, which could indicate that there is nothing in Bikini Bottom for him. On "Nautical Novice," Mrs. Puff says "We're going to flatten millions of innocent lives!"; which could mean that there are around 2 million people in Bikini Bottom. But in the episode What Ever Happened to SpongeBob?, there is a sign that says" Welcome to Bikini Bottom- Population: 538." However, this could indicate the downtown segment, which could indicate that Downtown is largely commercial. Whether SpongeBob knew about this is uncertain.