Outer Expanse

Outer Expanse is a region added in the Downpour DLC. It's separated from the rest of the world by a locked Karma Gate in the westernmost place of Subterranean. It is a lush and lively place, dotted with ruins of the Ancients.

Overview
Outer Expanse is a home to a number of unique creatures, the best known being the s. The Karma Gate was placed under lock-down by to keep the creatures of the place from ransacking his and 's facility grounds. It can be only explored by at first, once they meet Five Pebbles. After their ending is completed, the and the  gain access to the region as well.

Facility Roots (Western Intake)
The campaign starts in Outskirts right after exiting the Facility Roots.

Journey's End
The tree-home of the Slugcats seen in and  opening cutscenes can be found here.

Trivia

 * This region is the original homeland of Survivor and Monk, and quite likely the natural habitat of the species