Buhen was an ancient Egyptian settlement situated on the West bank of the Nile below the Second Cataract. On the East bank, across the river, was located an ancient settlement of Wadi Halfa. Buhen is known for its large fortress, probably constructed during the rule of Senusret III in around 1860 BC (12th dynasty).
Senusret III conducted four campaigns into Kush and established a line of forts within signalling distance of one another; Buhen was the northernmost of these. The other forts along the banks were Mirgissa, Shalfak, Uronarti, Askut, Dabenarti, Semna, and Kumma. The fortress itself extended more than 150 metres (490 ft) along the west bank of the Nile. It covered 13,000 square metres (140,000 sq ft), and had within its walls a small town laid out in a grid system. The fortress also included the administration for the whole fortified region of the Second Cataract. The walls of the fort were about 5 metres (16 ft) thick and 10 metres (33 ft) high. The fortress at Buhen is now submerged under Lake Nasser as a result of the construction of the Aswan Dam in 1964.
The two volumes of the monograph dedicated to Buhen by D.R.McIver and L. Woolley are now available online in PDF.