It was named by the IAU in 1970 after Swiss-American astronomer Robert Julius Trumpler (1886–1956).

This is an old, eroded crater with an outer rim that has been damaged in places by subsequent impacts, especially along the southwestern section.

The rim edge has been worn to the point where it is now poorly defined, and forms an uneven ridge in the surface.

A short chain of small craterlets extends from near the crater midpoint to just outside the eastern rim.

[citation needed] By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Trumpler.