It is shut in on every side by mountains: on the north by those in the Teri tahsil of Kohat District; on the east by the southern extremity of the Maidani Pahar or Khattak Niazi range and the northern spur of the Marwat range, which separate the District from the Isa Khel tahsil of Mianwali District in the Punjab; on the south-east and south the Marwat and Bhittanni ranges divide it from Dera Ismail Khan; and on the west and north-west lie Waziristan and independent territory inhabited by the Bhittanni tribe.

The highest point of the Maidani range at its centre, near the hamlet and valley of Maidan, has an altitude of only 4,256 feet.

The Marwat range culminates in Sheikh Budin, the hill which rises abruptly from its south-west end to a height of 4,516 feet, and forms the summer retreat for this District and Dera Ismail Khan.

From these ranges numerous spurs jut out into the Bannu plains, but no other hills break their level expanse.

Of the rivers the larger is the Kurram, which, entering the District at its north-western corner close to Bannu town, runs at first south-east, then south, and finally winds eastward through the Darra Tang or 'narrow gorge' which lies between the extremities of the Maidani Pahar and Marwat ranges.

The Tochi river enters the District about 6 miles south of the Kurram and flows in the same direction, gradually drawing closer to it until their streams unite about 6 or 7 miles west of the Darra Tang.North Waziristan, on the other hand, was an agency in the province bordering Bannu District.

Between the Kaitu and Tochi lie the Sheratulla and, north of Miram Shāh, the Dande — two barren plains, each about 30 square miles in area.

The loftiest peak is Shuidār (11,000 feet), at the western end of the Khaisora valley.After independence, Bannu District became a part of the then-much-larger Dera Ismail Khan Division.

This entirely and fully merged the seven agencies of the Federally Administered Tribal Areas and the six Frontier Regions with the province of Khyber Pakhtunkhwa.