Banachiewicz is a largely degraded lunar impact crater that is located near the eastern limb of the Moon.

Portions of the western and southwest rim still survive as low ridges in the surface, while the remainder is a jumble of irregular terrain with little definition.

The visibility is more than partly affected by libration, which can at times completely conceal this formation from view.

Just to the northeast of this formation is the large walled plain Neper, which lies on the southern edge of Mare Marginis.

By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Banachiewicz.