Tamm is a shallow lunar

Moon

The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

 impact crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

. It is located to the west-northwest of the much larger and more prominent crater Chaplygin

Chaplygin (crater)

Chaplygin is a large lunar impact crater that lies on the far side of the Moon. It is located to the southeast of the huge walled plain Mendeleev, about mid-way between the craters Schliemann to the northeast and Marconi to the southwest. It is about the same size as Albategnius on the near...

. Attached to the south-southwestern outer rim of Tamm is the smaller van den Bos

Van den Bos (crater)

Van den Bos is a small lunar crater that is joined to the south-southwestern outer rim of the slightly larger crater Tamm. About one crater diameter to the west is Vil'ev. Farther away to the east is the prominent Chaplygin, and to the south-southwest lies Marconi...

. There is a gap in the southern rim where these two craters are joined together.

The rim of Tamm 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.

Satellite craters

By convention these features are identified on lunar maps by placing the letter on the side of the crater mid-point that is closest to Tamm.

Tamm	Latitude	Longitude	Diameter
X	2.7° S	145.5° E	13 km