Sumner is a lunar impact crater on the far side of the Moon, beyond the northeastern limb.

It is southwest of the larger crater Szilard, and southeast of the twin walled plains Fabry and Harkhebi.

This crater formation has been heavily damaged by a history of impacts, leaving an irregular, battered outer rim.

[1] Starting about 30 kilometers to the north of Sumner and progressing to the east-southeast is a long, linear chain of craters that forms an irregular cleft in the surface.

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