The Gray Waste is a spatially infinite plane, consisting of three layers or sub-planes, sometimes referred to as the Three Glooms.

As an outer plane, Arborea is spatially infinite, further consisting of three infinite layers (or sub-planes).

As an Outer Plane, the Beastlands are spatially infinite, further consisting of three infinite layers (or sub-planes).

We can, of course, suggest that the universe is not spatially infinite and comes to an end somewhere, but the notion of an edge to space is paradoxical.

As with other outer planes, Arcadia is spatially infinite, consisting of two infinite layers or sub-planes.

These implicitly assume either that the universe is spatially infinite or that there are infinitely many universes.

These models propose that while the universe, on the largest scales, expands exponentially it was, is and always will be, spatially infinite and has existed, and will exist, forever.

Bytopia is a spatially infinite plane, consisting of two layers or sub-planes.

Like other outer planes, the Abyss is spatially infinite.

All Outer Planes are spatially infinite but are composed of features and locations of finite scope.