What is the largest crater on the far side of the Moon?

The South Pole–Aitken basin is the largest impact crater, or impact basin, on the far side of the Moon. It stretches roughly 2,500 kilometers across and reaches about 6 to 8 kilometers deep in places, making it one of the largest and oldest impact structures in the Solar System.

The basin occupies much of the Moon’s southern far side, extending from the South Pole toward the crater Aitken. Its immense size and great age mean that later impacts have heavily modified its surface, so its boundaries are not always obvious in ordinary photographs.

Scientists study South Pole–Aitken because a colossal impact may have excavated material from deep within the lunar crust or upper mantle. Samples from the basin could therefore reveal important information about the Moon’s interior and early history. China’s Chang’e 4 mission landed within the basin in 2019, on the far side of the Moon.

The word “crater” can cause confusion because this feature is more accurately described as a basin. Imbrium is another enormous lunar basin, but it lies on the near side; Copernicus and Tycho are much smaller, younger craters.