The Lost Museum was located either below or on Level 4, within Coruscant's forbidden levels. Situated amidst rocky terrain, the museum appeared to be carved almost entirely out of the stone surrounding it. It displayed statues of humans, tall structures, and an animal with the appearance similar to a fathier. The structure had multiple coral-like blue, white, and pink bioluminescent flora growing throughout it, which lit up the interior of the museum. Stone pots and a chest with necklaces hanging from its lid could also be seen in the museum's interior among the statues and displays. Round yellow stones, or coins, could be seen about or in piles throughout the interior.
After tricking Leia into coming with her, Holdo led an expedition into Coruscant's forbidden levels to find the Lost Museum after reading about it. Making their way through Coruscant's underworld, they came across a woman who, after telling Leia to place her hands on a purple glowing ball which she called a "Liga Crystal," made Leia's hands glow, stating "It's glow will guide you toward that which you seek." This would then prove as a useful tool as her hands now glowed brighter the closer they were to the museum. With this, they then used the piping in Coruscant's underworld to make their way into level 4, and after a brief chase with a criminal gang, they found the museum.