Alexander is a lunar impact crater-like feature in the rugged surface to the north of Mare Serenitatis.

[2] The Alexander formation has been so heavily worn and distorted with the passage of time that it now resembles little more than a lowland region enclosed by rugged ranges.

The rim segments lie along the northwest, west, and south sections of the crater, while the eastern side stands open to the surrounding surface.

The crater floor is more smooth and has a darker albedo in the western half, and gradually grows lighter and more impacted toward the east.

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