Cysatus is a lunar impact crater that is located in the southern part of the Moon's near side.

It is joined to the northeastern rim of the larger crater Gruemberger, and intrudes slightly into the interior of that formation.

This circular crater is slightly unusual for its lack of interesting features.

No notable craters lie along its rim or the flat, level interior.

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