An unusually elliptical crater, it measures roughly 180 by 220 kilometers and is located near the equator near the center of Tethys's trailing hemisphere at 10.8°S, 249.2°W.

[2]: 3  Nevertheless, with an average diameter of roughly 207.5 kilometers,[1] it is the fourth-largest known impact structure on Tethys.

Within Penelope's basin floor is a heavily degraded central peak ring approximately 50 kilometers in diameter.

The central peak ring's northern and southeastern arcs are the best-preserved sections of this feature.

[4]: 10  Penelope is rather deep and unrelaxed, having not been flattened out as with some of Tethys's other major impact craters.