The rim of Furnerius is worn and battered, with multiple impacts along its length and notches along the base.

Much of the wall now rises only slightly above the surrounding terrain, with the lowest sections to the north and south.

In Johann H. Schröter's lunar study of 1791, he sketched this crater with a low dome in the southern half.

This feature has proven difficult to identify in subsequent lunar photographs and observations.

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