Large-scale structure is the distribution of galaxies and other forms of matter on a distance scale of about 100 million light-years or greater.

The visible large-scale structure of the universe is sponge-like, with galaxy superclusters arranged into enormous filaments and sheets that are separated by giant voids where very few if any galaxies reside.

Among the nearest components of the cosmic large-scale structure are the Local Supercluster, the Great Wall, the Great Attractor, and the Shapley Concentration. In addition, observations by the Chandra X-ray Observatory have revealed part of an intergalactic web of hot gas and dark matter that is crucial in defining the cosmic landscape. The hot gas alone, which appears to lie like a fog in channels carved by rivers of gravity, is more massive than all the stars in the universe. Its detection may eventually enable astronomers to map the distribution of dark matter.