The expansive desert region on the Outer Rim planet Tatooine, referred to as the Dune Sea or the Great Dune, encompassed a large area. Within the Dune Sea existed the Great Pit of Carkoon, the habitat of the sarlacc. The Mos Espa Grand Arena could be found in the Western Dune Sea. In contrast, the palace belonging to Jabba the Hutt, as well as the home of Obi-Wan Kenobi, were situated outside the boundaries of the Dune Sea.
Fossils uncovered by archaeologists implied that prior to the Imperial Era, the Dune Sea was a body of water that evaporated due to Tatooine's twin suns, Tatoo I and Tatoo II. Jawa legends indicated that the Dune Sea had previously been an ocean. Despite the difficulty many colonists had in accepting that water had once been plentiful on Tatooine, the ancient fossil-filled rocks and worn canyons appeared to support the Jawa stories.