Largest Constellations by Area

About This Dataset

This chart ranks the largest of the 88 official constellations by the area of sky they cover, in square degrees, as defined by the International Astronomical Union. Hydra, the water snake, is the largest.

✨ AI Insight

Hydra, the water snake, is the largest constellation, sprawling across 1,303 square degrees, more than 3% of the entire sky. It narrowly edges out Virgo (1,294) and Ursa Major (1,280), home of the Big Dipper. The top five, completed by Cetus and Hercules, each exceed 1,200 square degrees. These figures come from the International Astronomical Union, which in 1930 divided the sky into 88 constellations with precise boundaries, so every point in the sky belongs to exactly one. Size here reflects the area of those official boundaries, not brightness or star count, which is why a large constellation like Hydra can still be faint and hard to trace. For comparison, the smallest constellation, Crux, covers just 68 square degrees, about nineteen times smaller than Hydra.

Source: IAU designated constellations by area

Key Findings

Auto-computed highlights from this dataset

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Hydra leads with 1,303 in All Time.

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Average value in All Time: 1,172 · median: 1,182.

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Gap in All Time: Hydra is 1.3× larger than Aquarius.