The Ice Kingdom is a setting in Adventure Time. It is made up of hundreds of pointy, snow capped mountains, as well as several snowy hills. It is the location of the Ice King's castle as well as the home for a variety of ice-themed creatures. The Ice Kingdom's population is fairly sparse, by the look of things, especially compared to other kingdoms in the land. The population consists mostly of penguins, with the occasional elemental creatures conjured by the Ice King himself. The Ice Kingdom is bordered on at least one side by water, and is visible from Finn and Marceline's home.
Ice King's Castle
The only known building in the kingdom is the Ice King's Castle. The castle is basically a hollow mountain capped by snow and ice, with the main entrance being a face-like set of windows near the top. Ice King's main living room has a fancy bed, a drum kit, and gym equipment. It usually has underpants and old pizza boxes on the floor. There is also a cage where Ice King kept princesse he had kidnapped until his murder by Billy. There are several secret rooms including what appears to be a basement filled with monsters and technology and a secret chamber full of ninja collectibles seen in. It is shown there is a large network of tunnels and open spaces in the castle, as well as a kitchen and dining room. It is also shown Ice King built a room in his basement with a portal to the Spirit World, which is actually the Mystery Cave. This room seems to have fog billowing on the floors.