Measured by botanist Stephen C. Sillett, it is the world's third-largest coast redwood, the largest being Lost Monarch.

Like many old growth redwoods, trunks within the crown are hydraulically linked by fused branches.

[2] This redwood tree was named by Sillett after Eru Ilúvatar, the creator of the universe in J. R. R. Tolkien's legendarium, in which his novels The Hobbit, The Lord of the Rings and The Silmarillion take place.

The Atlas Grove (with Iluvatar) is said by author Richard Preston to have been discovered by naturalist Michael Taylor in 1991.

Neighboring species include Pseudotsuga menziesii, Picea sitchensis, Acer macrophyllum, Rhamnus purshiana, Umbellularia californica, Tsuga heterophylla, Chamaecyparis lawsoniana and Lithocarpus densiflorus.