The Pyramid of Userkaf. In the background the Pyramid of Teti

Userkaf was the first ruler of the 5th Dynasty. He was the grandson of the successor of Khufu, Djedefre who died early. His mother was Queen Neferhetep or possibly Khentkawes but his father is unknown. He married Khentkawes who was the daughter of Menkaure. Userkaf broke with the traditon of the 4th Dynasty rulers and built his pyramid close to the north-east corner of the Djoser Complex at Saqqara. Nowadays it is called the 'Ruined Pyramid' as the outer casing was robbed in antiquity. The whole pyramid now looks as a mound of rubble.

There was an entrance on the north side, from a court. A sloping passage led south to a storeroom, an antechamber and the burial chamber. Both chambers were lined with white limestone. The ceilings are lined with big limestones and entrance to them was originally blocked with a portcullis of pink granite. The empty sarcophagus was of black basalt with no decorations.

A head of Userkaf, in the Cairo Museum.
Photo: www.egyptarchive.co.uk

The Mortuary Temple and Causeway
The location of the mortuary temple deviated from tradition by being built on the south side of the pyramid, whereas earlier such structures had been located on the east or north side. But its architecture seems to have been according to the standard way, even if they´re arranged differently, being oriented towards the south instead of towards the pyramid. This is also where the causeway entered the enclosure. There are different opinions as to why this is; either the orienteation might be a homage to the Heliopolitan sun worship,which the kings of the 5th Dynasty were much involved with, or it might have been that the ground to the north wasn´t suitable for building on. But also, Userkaf seemed anxious to build as close to the Djoser Complex as possible, which could be another reason for its unusual plan. And there have been suggestions of a large moat surrounding the Djoser enclosure, if this was so, then Userkaf might have placed his pyramid where it is for practical reasons.

The mortuary temple had a vestibule and next an entrance hall. After this came an open court with granite columns. Among the rubble here was found a very big head of Userkaf. To the south of this court, was a small columned hall and behind it was five niches for statues of the king, which in this case had been facing the pyramid. There was also a sanctuary and store rooms, they too were oriented towards the south. The causeway is yet not excavated, neither has his valley temple been found.

The Offering Chapel
The offering chapel, just as the mortuary temple, had a floor of black basalt. There was a main room with a false door of quartzite. On both sides of it were narrow chambers. The walls were made of granite at the base and the rest was of Turah limestone.

Satellite Pyramids
There was a satellite pyramid southwest of the main one, within the enclosure. It was 21 m square and had an underground chamber with its entrance to the north.

Outside of the enclosure, to the south, was yet another pyramid measuring 26.25 m to a side.It was structured like Userkaf´s but smaller and without any storerooms. It also had its own mortuary temple and was apparently build for a quen, whose name has been lost.


Sources:
The Complete Pyramids - Mark Lehner
The Complete Royal Families of Ancient Egypt - Aidan Dodson
Chronicles of the Pharaohs - Peter A. Clayton
Three very good links:
Saqqara Online
Egyptsites
Touregypt