The 70 km × 80 km sedimentary basin of Bannu is surrounded by hills on all sides, with the high mountains on the Afghan border on the west and north-west. The Kurram and Tochi rivers provide the perennial drainage and some major communication lines with Afghanistan, and although vegetation at present is highly degraded, what has been suggested for Baluchistan may also be suggested for Bannu: there is no clear evidence of climatic change over the past few millennia. Irrigation is practised along the river courses but dry-farming areas depend more on pastoralism than on agriculture. Of all the sites excavated in the region, Sheri Khan Tarakai, located on the bank of a non-perennial stream of the Tochi system, is the most important, both because of its antiquity and the clearly documented details of cultural remains. The calibrated date range is c. 4500–c. 3000 BC. Mud-brick houses on stone/boulder foundations were common, along with an impressive set of saddle querns and mullers, ring-stones, ground celts, microlithic industry, bone tools, occasionally painted terracotta bull and female figurines, terracotta spindle-whorls, cultivation of barley, use of sheep, goat, cattle and buffalo, freshwater gastropods suggesting a greater reliability of water source in the past, chank shells of the Indian Ocean variety (Turbinella pyrum), and two major categories of painted pottery. One of these is a coarse handmade type with thick black-slipped exterior and a burnished pinkish buff to cream-slipped interior with black or brownish painted designs which include standing caprids. The external surface of the second type is roughened with the application of a thick slurry of clay, although the neck and the shoulder may be unroughened and decorated. Interestingly, metal is absent in this level which is thus considered ‘neolithic’.
The third millennium BC levels in Bannu are associated with the Kot Diji culture of the plains and have been excavated at Tarakai Qila, Lewan, Islam Chowki and Lake Largai, all in the Tochi-Baran interfluve. At Tarakai Qila, mud-brick architecture with massive walls in places has been found along with wheat, barley, lentil and field-pea, whereas at Lewan there is only a series of excavated pits without any clear architectural association. Otherwise, however, Lewan gives the impression of being a production site of stone objects like querns, mullers, ground stone artefacts, etc. Islam Chowki is interesting for the evidence of a damaging flood during its prehistoric occupation which has among other things sheep, goat, cattle, horse/ass, wheat and barley. Lake Largai had, in addition, bones of rhinoceros. On the whole, the Bannu basin offers an uninterrupted sequence of village occupations right from the middle of the fifth millennium BC.