Usually, they are places in an existing level, but that is not always the case. They may also contain rooms locations that are too small to be considered their own level. Levels often contain sub-levels levels that are related to their parent level, but are still their own distinct level. The laws of physics and nature as we know them cannot be relied on in the depths of the Backrooms nevertheless, some of the more hospitable and stable levels are home to thriving communities, and some inhabitants have managed to survive in even the most dangerous levels.
Typical levels-for whatever value of 'typical' can be expected from the Backrooms-tend to be infinite in size (though 'bounded' levels are not unheard of), and often provoke a feeling of uncanny familiarity to those happening upon them. … normal levels form the framework of the Backrooms, and vary greatly in size, danger, and habitability.