Shalfak is an Egyptian fortress on an island in the Second Cataract area. It was built in the heyday of the Middle Kingdom, under Senusret III (c. 1870–1850 BC). It is one of a chain of 17 fortresses which the pharaohs of the 12th dynasty established to secure Egypt's southern frontier against the (perceived) threat from the Kingdom of Kerma.
The fortress occupies a roughly triangular area of c. 1800 square metres. Its mudbrick enclosure wall is about 8 metres thick and still stands up to 6 metres high. Three spur walls, towards the north, west and east, complete the fortification system. The eastern wall protects the stairway leading down to the river.
The interior of the fortress can be accessed through two gates in the north and in the south. The internal structures are very well preserved. They comprise a command building, barracks, workshops, storerooms and a granary.
Shalfak is one of only two fortresses which have survived above the waters of Lake Nasser/ Nubia – the other one being Uronarti, about five kilometres upstream. Their isolated position has contributed to the excellent preservation not only of their architectural substance but also of organic building materials such as wood and reed.
It has been argued that the Middle Kingdom fortresses in Lower Nubia by far exceeded any military requirements and that they should be perceived as an ideological statement – destined to impress and to propagate Egypt's grandeur. Exploring these monuments and understanding this message 4000 years after their construction is a unique experience indeed.