Reimarus is a lunar impact crater, located in the southeastern part of the Moon's near side.

This is a heavily worn and eroded crater, with an outer rim that has been incised and battered by multiple lesser, later impacts, particularly in the western half.

Several small craterlets lie along the rim edge and the inner walls, and the outer rise is generally uneven and rugged.

The remainder of the floor is generally featureless and marked only by a few tiny craterlets.

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