A Triple Crater

This image from NASA's Mars Reconnaissance Orbiter shows an elongated depression from three merged craters.

The raised rims and ejecta indicate that these are impact craters rather than collapse or volcanic landforms. The pattern made by the ejecta and the craters suggest this was a highly oblique (low angle to the surface) impact, probably coming from the west.

There may have been three major pieces flying in close formation to make this triple crater.

https://photojournal.jpl.nasa.gov/catalog/PIA21652