They're impact craters. They occur, in varying sizes, on pretty much every solid body in the solar system but the number of preserved craters depends on the extent to which the surface of the body in question has been "resurfaced" (largely because cratering rates are much lower than earlier in the history of the solar system). Because of active plate tectonics and surface processes, Earth does not have many preserved impact craters, especially compared to the Moon, Mercury, etc, but there are a few well preserved ones, which are similarly quite circular.

Most craters are circular. There are elliptical craters (e.g., this example from Mercury), but they are relatively rare, accounting for only around 5% of craters (e.g., Bottke et al., 2000). Very specific conditions need to occur for an impact to generate an elliptical, as opposed to circular crater. One of the critical factors is the angle of impact, with shallow angles between the impact trajectory and the surface favoring ellpitical craters, but other conditions, like slow impact velocities, stronger target materials, and larger impactors, modulate what impact angle is able to produce an elliptical crater (e.g., Elbeshausen et al., 2013).