The Root is a Rain World mod created by Willburd that adds a new region that expands on the Subterranean and the Exterior. On November 17, 2019, Root 2.1 was released, creating a more cohesive region with new rooms.
The Root is comprised of two subregions and the main region. The main region takes up the large vertical center portion, with four shelters and a gate to the Exterior at the top right. The larger subregion is the Coastline Railway, which has three shelters and a horizontal landscape leading from the left side of the Root to the Subterranean. The final subregion is Penumbral Basin, which is a shorter area leading from the right side of the Root to the Shaded Citadel, with two shelters. Each area has pools of water on the lowermost regions.