It is worn and eroded, with multiple small craterlets along the edge and inner wall.

Most of the rim structure has been worn away by subsequent impacts and deposits of ejecta, and now forms a rounded dip into the curving interior.

A small chain of craters cuts across the rim and inner wall to the west-northwest.

Paschen lies to the east of the larger walled plain Galois, and to the southwest of the huge Hertzsprung.

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