Porter is a lunar impact crater that is located in the southern part of the Moon, and lies across the northeastern rim of the huge walled plain Clavius.

The outer rim is generally lower to the southwest, where it lies on the floor of Clavius.

The crater is somewhat worn in appearance, in comparison with the younger and sharper-edged Rutherfurd to the south along the southeastern rim of Clavius.

A small craterlet lies along the northwestern inner wall of the crater, but the formation is not otherwise significantly marked by smaller impacts.

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