Land of Ooo

The Land of Ooo is the main setting of Adventure Time, and is the home continent of Finn and Jake, along with all of their friends and foes. It is divided into many different kingdoms, of which the most prominent are the Ice Kingdom, Candy Kingdom, Castle Lemongrab, Wildberry Kingdom, Lumpy Space, Fire Kingdom, and Cloud Kingdom. There are also many geographical areas not known to be part of any kingdom, such as the Evil Forest and the Bad Lands.

Map
Frederator Studios released two different official maps of the Land of Ooo along with the original Adventure Time pitch documents: the black-and-white map and color map, both seen in the gallery below. Of these, the black-and-white one drawn by Ghostshrimp is probably more accurate for several reasons:
 * 1) Its general shape matches the aerial view of Ooo seen in "Business Time" (see picture in gallery below).
 * 2) A slightly modified version of this map appears on Princess Bubblegum's hologram map in "The Other Tarts."
 * 3) On the black-and-white map, the names of certain places match up with the names used in the show and by its creators, while some of the names on the color map do not.

Map-only locations
The two official maps show many locations that have never been mentioned or seen in the show. Nothing is known about them other than what appears on the maps.

On the color map, a Mystery Temple appears on an island off the east coast of Ooo. It resembles a. Also on the color map, the Fire Kingdom is labeled "Burning Lands" and the Grass Lands are called the "Verdant Plains." An area called "Red Rock Cliffs" might correspond to Red Rock Pass, and a note indicates that Marceline's cave is located there.

On the black-and-white map, there are many places that have never been seen in the show. To the north of Ooo is the Sea of Something, which contains a small island chain called the Shiney Isles, which appear to have crystals on them. The warrior known as The Farm hails from this island chain. On a northern peninsula near the Ice Kingdom are the Unknown Lands. In the comic, this place seems to have a purple hue. A cloud or island in the northwest corner of the map is called the Cloud Forest, which appears to be covered in clouds with trees on top of them.

The Sea of Sure Death is off of the southwest coast of Ooo, near the Lost Cliffs. The map shows a dragon in the sea near there. The Isle of Steam appears off the coast of Ooo next to the Fire Kingdom. Just to the south of it is the mysterious Chicken Blood Cove. The Squid Ink Sea is to the southeast of Ooo, and features several unidentified islands. In the ocean near there is a Whirlpool of Sharks. The Floating Gems appear to be diamond-cut isles floating in the sea on the easternmost edge of the Land of Ooo.

The Haunted Swamp is just east of the Grass Lands and north of the Spooky Forest. Strangely, in the hologram map that appears in "The Other Tarts," it is labeled "The Haunted Swan," though this is likely an error. The Hole Near the Center of the World is, as its name suggests, a hole near the middle of Ooo.

Government
Ooo exhibits a mix of democracy, dictatorship, feudalism, as well as what appears to be despotic monarchy in all of Kingdoms of Ooo except Fire Kingdom (an absolute hereditary monarchy), Ice Kingdom (a borderline of despotic or absolute monarchies as depends), and Candy Kingdom. Candy Kingdom in particular slowly developed into a mix of absolute monarchy authoritarianism beginning in Season 2, culminating in the Season 6 finale, when the land held its first (and most likely only) election to replace Princess Bubblegum. King of Ooo subsequently ruled the land for a few months, but the citizens eventually rebelled against him and reinstated Bubblegum. Most kingdoms are ruled by one or more members of royalty, such as the Ice Kingdom and Fire Kingdom. The Grand Meeting of Ooo Royalty shows that the various rulers of Ooo meet together (except Earl of Lemongrab) for discussions on a regular basis, though the topics are not revealed. A similar event called Princess Day is also held every year. No republics are known to exist in the Land of Ooo. Dictatorship is only exhibited in "The Silent King" where Xergiok takes control of the Goblin Kingdom by force, and by the Earl of Lemongrab, after the escape of Lemonhope, who turns the entirety of the Lemon Earldom into a totalitarian city-state until "Lemonhope Part 2" that is now a constitutional monarchy city-state after both Lemongrab 1 and Lemongrab 2 exploded and Princess Bubblegum stitched them together to create Lemongrab 3, who took over as ruler of the earldom of Lemongrab. Party Pat is the chief of the Bears, but they do not display any form of government, except for possibly nomadic tribal chiefdom as Pete described his group at end of his speech. In the episode "Paper Pete," Mildwin is the democratically elected leader of the Moldos. In the episode "The Mountain," the Mountain of Matthew seems to be a theocracy with the leader being Matthew, who is actually formed by several humanoids. The mountain's only guardian is also formed by several humanoids. This guardian acts as a holy guard to the Mountain of Matthew rather than a normal guard, as other guards are in the rest of the series so far.

Military
Ooo has also not been shown to have an army or any type of military force that protects the land as a whole. Therefore, each kingdom provides its own military or police force. The most prominent example of this would probably be the Candy Kingdom, which has fortified walls (albeit candy ones) and the Banana Guards, along with other security forces. On the other end of the spectrum is the City of Thieves, which appears to have no police force whatsoever, and all of the citizens constantly steal from one another.

One could argue that Finn and Jake are the official military, but it has not yet been confirmed.

Religion
One of the primary deities worshiped in Ooo is Grob Gob Glob Grod. The Cosmic Owl apparently is also known as some kind of spiritual entity that appears in premonition dreams. Ooo seems to have a number of other potentially godlike beings such as Party God and Death.

In "Video Makers," Shelby wears a  often worn by Christian priests. In "The Pit," Shelby and his collar reappear, and it is revealed that Shelby can actually bless objects, imbuing them with a certain degree of holiness. Although it may just be a throw-away joke, this turn of events seems to suggest Shelby may actually be some sort of priest.

In "Holly Jolly Secrets Part I," many Christmas-themed items appear, but none of the characters show knowledge of the holiday itself (instead of Christmas, the holiday is called a day for wearing sweaters and watching secret tapes). Natasha Allegri has stated that the picture of a mother and child in Marceline's house is of The Madonna and baby Jesus. However, there's no direct evidence that Marceline actually holds religious beliefs, and the significance of the picture has never been addressed by the characters. Since Marceline is over 1000 (and is shown in "I Remember You" as having lived through the "Mushroom War"), if anyone remembers, it would presumably be her.

In the episode "Marceline's Closet," just before Finn and Jake play Cloud Hunt, Jake mentions a central Buddhist philosophy. When asked what he is doing, Jake responds with, "Eliminating desire from my heart. It helps pass the time." This is the ultimate goal of the Eight-Fold path and a central idea behind the four noble truths. Jake has also stated his belief that when he "croaks" his consciousness will become one with everything while Glob tallies his deeds. This statement is a rough combination of several religious beliefs; that upon dying one's soul becomes part of everything and that one's deeds in life determine the soul's fate after death.

In "Bad Little Boy" Ice King mentions God, but the Christianism may not persisted, due the fact that he is older than the Mushroom War.

In the episode "The Vault," the Regression Simulator game on BMO announces that it is the hypno-priest.

In the episode "The Mountain," Lemongrab 3 goes on a seemingly spiritual quest to merge with Matthew, who religiously believes that he could fix everything though world domination.

Rebecca Sugar has stated that Abraham Lincoln is the equivalent of Jesus in Ooo.

Currency
The only currency shown in the series is dollar bills and coins, although some store owners (Choose Goose) prefer. The dollar is made in at least two sizes (regular and giant). The dollar is first shown in "The Enchiridion!" when Finn steals a giant dollar from an Ogre. The dollar is also seen in "To Cut a Woman's Hair," when Finn pays Simon to play his violin. The dollar probably does not come in tiny size, because then Finn would have used a tiny dollar to pay Simon. Dollars appear again in the episode "Donny" when Mr. Bank puts himself together. Also, in the episode "Hitman," the Ice King tries to pay Scorcher not to kill Finn and Jake. Gold and jewels are also used, and even accepted as a form of tax payment in "Burning Low." In "Be More," an LMO waves a dollar bill while another one rolls a pair of dice.

There is also a penny shown in "Sons of Mars," when Abraham Lincoln tries to use it as payment (and apparently has succeeded before). In "Guardians of Sunshine" Jake attempts to take one of the game's coins to the real world, but, much to Jake's disappointment, it turned into a penny when it was removed from the game.

There are also other coins shown in "Davey" when Finn takes some from a fountain. In the episode "James," James used a coin to fix the radio signal.

Languages
 seems to be the primary language in Ooo, though many others seem to be spoken:
 * : Rainicorns speak and write in Korean; Jake and Princess Bubblegum can understand it, but they speak it infrequently, if at all.
 * : In "What Have You Done?," "Frost & Fire," and "Go With Me," Princess Bubblegum spoke a bit of German. Also, in The Adventure Time Encyclopædia, German is said to be the preferred language of demons.
 * : As shown in "Incendium," the Flame King speaks some when talking to Jake. Jake sings , a song sung in French, in "Holly Jolly Secrets Part II." Also, in "The Real You," when Finn's finger and Jake are in the Apple Classroom, a poster at the back of the room can be seen, with the month "Avril" (French for April) written on it.
 * : In "Marceline's Closet," Jake says a Japanese phrase. Jake also spoke some Japanese in "Return to the Nightosphere." And in "Gut Grinder," one of the soft people called Jake "kawaii" (meaning "cute"). In the episode "Candy Streets," when Finn and Jake enter the Pharmacy, on the wall behind Ann are the  characters "ファーマシー" (fāmashī) which mean "Pharmacy." In "One Last Job," Jake stretches his arm into a hole in a log in the wall; it is hollow inside and Jake is shown reaching up to it. When Jake's hand reaches the top of the inside of the hollow log, he is seen pressing a button with a label above it in which appears to be Japanese text.
 * : In "Hug Wolf," the book Jake consults to discover what sort of beast Finn turns into after he is hugged by the alpha hug wolf, has its title in Latin. Also the wizard Bufo, who first appears in "Wizard," takes his name from the Latin word for toad: "bufo." The incantation used to open a portal to the Nightosphere ("Maloso vobiscum et cum spiritum") is also pseudo-Latin and is an inversion of the actual Latin phrase, "Dominus vobiscum, et cum spiritu tuo" (meaning, "May God be with you, and with your spirit") often used in the Latin Catholic mass. Finn also speaks Latin while facing off against the Gladiator Ghost in "Morituri Te Salutamus." Similarly, the spell to summon Kee-Oth the Blood Demon appears to be engraved in pseudo-Latin and reads: "BUTYRUM LAC SUREPO KEE OTH PRADIUM." This translates, albeit very roughly as, "Buttermilk, syrup, breakfast, Kee Oth."
 * : In the episode "The Party's Over, Isla de Señorita," several Spanish words and phrases are spoken, particularly when Island Lady sings about Ice King hanging around with her. In fact, the phrase "Isla de Señorita" is a Spanish phrase which translates to "Island of Lady." In "Paper Pete," one of the books Finn runs past as he brings the Moldos to Jake reads "Carne," Spanish for "flesh." On the same shelf, another book reads "Diccionario de los Muertos," which translates to "Dictionary of the Dead."

Post-apocalyptic setting
Pendleton Ward, the creator of Adventure Time, has stated both in an interview and in his FAQ page that the Land of Ooo is actually a post-apocalyptic Earth, the result of a global disaster called the Mushroom War, hence the ruined pieces of modern technology scattered across the land. From ”Son of Mars“ and "Orgalorg", it is revealed that Ooo is very close to the massive crater if not inside it; The Crater seemed to be covering what used to be Europe.

It is possible that Finn may be the sole human being left in Ooo. It is also possible that the Mushroom War is responsible for killing off all the other humans, or that they mutated into the current and varied inhabitants of the planet. In "Her Parents," Lady Rainicorn's parents mention that they wanted to eat Finn because they never thought they would get the chance to eat an actual human, implying they are either extremely rare or extinct.

For more information on Finn as the last human, see the "Status as the last human" section on Finn's article.

In "Simon & Marcy," the Land of Ooo (or at least part of it) used to be a pre-Mushroom War territory or country called the "Wut-Wut State" as shown on a food truck's registration plate.

Trivia

 * While Pendleton Ward says the Land of Ooo is a continent, Adam Muto says it is the size of a smallish island nation. The maps lend more evidence to the latter. Princess Bubblegum refers to Ooo as a continent in the short Have You Seen The Muffin Mess.
 * The map of Ooo vaguely resembles an eagle or phoenix.
 * On the Cartoon Network advertisement for "Adventure Travel," the Land of Ooo is shown as a rolling plain rather than a continent.
 * In The Adventure Time Encyclopædia, the Land of Ooo is shown on the first page and Jake added some more landmarks.