994 mi in diameter and with a floor 2.5 km below the average planetary surface altitude, and has been suggested to be an ancient buried impact basin, though this is contested. It has several features in common with lunar maria, such as wrinkle ridges. The density of impact craters in the 100 to 2000 m range is close to half the average for lunar maria.

Chryse Planitia shows evidence of water erosion in the past,