Dimension

A Dimension in Minecraft is a huge procedurally-generated world to explore. In the vanilla game, there are three dimensions: the Overworld, the Nether, and the End. Many mods add new dimensions, including the possibility for the player to create many custom dimensions in the same save.

Vanilla Dimensions

The following is dimensions that are part of the core Minecraft World:

Dimension	DIM-ID	Mod	Access	Description
Nether	-1	Minecraft	Nether Portal, a minimum of a 4x5 obsidian frame set on fire	Also known as Hell, the Nether is a giant cavern full of Netherrack, Lava, and dangerous mobs. Traveling one block in the Nether is equivalent to traveling eight blocks in the Overworld.
Overworld	0		initial spawn	The standard Minecraft world, with myriad biomes and standard ore generation.
The End	1		End Portal, found in an overworld Stronghold and activated with Eyes of Ender	Also known as Sky, the End is a floating island of End Stone full of Endermen and guarded by the Ender Dragon boss.

Dimensions added by mods

These are Dimensions only available if the relevant mods are installed:

Dimension	DIM-ID	Mod	Access	Description
Age	varies	Mystcraft	Descriptive Book	Fully customizable dimensions, these can have features such as eternal day, no weather, and instability. Terrain generation can be anything from a complete void to a replica of the Overworld, but will always contain a spawn platform and Abandoned Libraries. Any number of different Ages can be created in the same server/save.
RFTools Dimension	varies	RFTools	Dimlets	Fully customizable dimensions which need RF power to create and maintain. Needs the RFTools teleportation system to get there.
Deep Dark	-100	Extra Utilities	Portal to the 'Deep Dark'	Also known as the Underdark, this is dark cave world with riches and dangers alike. Most Ore generation is doubled, but hostile mobs are stronger and can spawn regardless of light level. Additionally, any player that strays too far from a light source will take damage from the darkness itself.
The Last Millennium	-112	Extra Utilities	Portal to The Last Millennium	Also known as The End of Time, this is a void dimension where there is nothing anywhere except a single platform with a streetlamp and The Last Villager. This dimension is a very noticeable reference to Chrono Trigger, but it is also a great place to just build for people who like to build in void dimensions.
Compact Machines 3	144	Compact Machines 3	Compact Machine	Dimension in which all micro machine builds are stored with ~1k blocks between each other.
Moo Moo Farm	-31	Ars Magica 2	Activating a Gateway with an Evil-Looking Book (a one-way trip!)	It's all just evil cows.
Bedrock	-19	Thaumic Tinkerer 1	Bedrock Portal	Created when trying to mine bedrock with an Awakened Ichorium Pickaxe on Line mode. Filled with bedrock that is incredibly fast to mine and a high density of ore.
Twilight Forest	7	Twilight Forest	Twilight Forest Portal, a 2x2 water pool surrounded by flowers/grass/mushrooms, with a diamond tossed in	A world in eternal dusk, this dimension includes many unique landmarks, creatures and enemies, including several bosses.
Spirit World	9	Witchery	Entering the Spirit World can be done one of a few ways. A player can eat an Apple of Sleeping, drink a Brew of Sleeping, or go through a Spirit Portal.	Dreaming in the Spirit World can come in two forms, a good dream or a Nightmare. When the Spirit World is a Nightmare Nightmares roam is and all the Wispy Cotton is tainted and is instead Disturbed Cotton. Disturbed Cotton though can be gathered to make a Dream Weaver of Nightmares to make the chances of a good dream better.
	-37
Torment	-38		To initially enter the Torment dimension, the player must summon the Lord of Torment using a Torment Scroll. Then, they must battle it until it has half of its health depleted (250 health points, or 125 hearts of health points). When this point is reached, the player and boss will be teleported into the dimension.	The Torment Dimension is a series of mazes with treasure rooms (3 per maze) and the floors of the paths made from Torment Stone. The walls and the ceiling are made of an invisible bedrock-like block (breakable in Creative Mode). At the end of each maze there is a portal which will transport the player back to the overworld.
Mirror Dimention	-39		Magic Mirror	A dimension of 9x9x9 rooms separated by mirror surface blocks. When you first enter this dimension the demon trapped inside will take on the form of the player who enters the mirror and try to kill them. Once the demon has been slain the mirror will turn into a hollow mirror, the demon won't return leaving you a room to do what you want with. Also the mirror surface blocks can not be broken however placing another mirror on one of the walls and having an altar nearby will allow you to travel between the rooms.
Spatial Storage Dimension	varies	Applied Energistics		Used for Spatial Storage, players may be transported too, and trapped if they're not careful.
Promised Land	20	Biomes O' Plenty	Promised Land Portal, created by using an Ancient Staff	A dimension of floating islands, hostile mobs are not meant to spawn here. This is the only place to acquire Amethyst. Falling into the void will send the player to the Overworld, at max build height.
Anu's Castle	-34	Fossils and Archeology	This is where Anu, The Ancient Pigman Overlord, has been banished, to make a portal to this dimension a statue of Anu must be found and surrounded in redstone and four Ancient Figurines of any type.	This dimensions is a Nether-based hellscape that is primarily a massive castle filled with loot and lifeless Anubite Statues that attack. Anu must be fought and beaten in order to leave.
Mining World	6	Aroma1997's Dimensional World	Just craft some Stone Bricks together with a Pickaxe and you get a special kind of Bricks. They are a little harder to break than normal Stone Bricks and they open you up the ability to visit a new world, the Mining World. Just build a five blocks high and four blocks wide wall with a three by two hole in the middle(same shape as a Nether Portal). Then you need a new Tool to actually create the Portal. Craft a few Stone Bricks, a Flint and Steel and a Stick together to get the Portal Igniter (Portal Multitool). Then right-click the Portal Frames with it.	Similar to the overworld, but completely flat. Intended for mining and quarries.

Dimension file formats

• Overworld doesn't have its own folder regardless of it being identified as DIM0
• DIM## = Non Mystcraft world
• DIM_MYST## = Mystcraft world.