Tamm is a shallow lunar impact crater. It is located to the west-northwest of the much larger and more prominent Chaplygin crater. Attached to the south-southwestern outer rim of Tamm is the smaller Van den Bos crater. There is a gap in the southern rim where these two craters are joined together.
The rim of this crater is worn and eroded, with old impact rims incising the northern edges. The rim edge is now a circular, uneven ring of ridges. The interior floor is level and is marked only by tiny craterlets and a few clefts along the edges. The floor has merged with the interior of Van den Bos to the south.
|X||2.7° S||145.5° E||13 km|