Geological Chronicle
Wilhelm is a lunar impact crater in the southern part of the Moon, situated to the west of the prominent Tycho crater. Measuring 100.83 kilometers across, the formation is of the type traditionally termed a walled plain. Ray material from Tycho extends across both the rim and floor of the crater.
The crater has a heavily eroded outer rim overlain by several smaller craters. Wilhelm A and Wilhelm K lie across the southwest rim, with Wilhelm B situated just to the northwest along the western rim. Wilhelm C intrudes into the north-northeast rim, and Wilhelm D is attached to the northeast outer rim. An outward protrusion in the southern rim extends to contact the crater Montanari, while Lagalla is attached to the southwest and Heinsius lies to the north-northeast.
The interior floor of Wilhelm is relatively level, marked by a rougher area to the northeast while the remainder is flat and almost featureless except for a few tiny craterlets. The crater is named for Wilhelm IV, Landgrave of Hesse, a German astronomer.