Pharaoh Shepseskaf was the last ruler of the Fourth Dynasty and reigned for perhaps 5 years. The Mastaba of Shepseskaf (also known as 'Mastabet Pharaon') is located a few dozen meters southeast of the 6th dynasty pyramid of Pepi II, in the southern section of the Necropolis of Saqqara. The mastaba's construction expresses Shepseskaf's refusal to the sun-cult and the building of the pyramid as the burial of the king (being linked to the sun-cult).
The tomb takes the shape of a rectangular sarcophagus, 100 m in length, 71 m in width, and 18 m in height. It has a complex, the Valley Temple of which has not yet been discovered. The entrance is a couple of meters up on the north side. There are some remnants of a pyramid temple on the east side, with part of the causeway. Also found was a mud brick perimeter wall, some 15 meters away the edge of the mastaba.
You can get more information here.