The city of Isakhel is the headquarters of the tehsil which is administratively subdivided into 3 Municipal Committees and 13 Union Councils.
According to the 1901 census, it contained the municipalities of Isakhel (population, 7,630), the headquarters, and Kalabagh (5,824); and 43 villages.
Lying on the west bank of the Indus, this tehsil is cut off from the rest of the District, and would seem to belong more properly to the North-West Frontier Province, but is separated even more completely from Bannu by the semicircular fringe of the Chichali and Maidani hills, which leave it open only on the river side.
Its extreme northern portion, known as the Bhangi Khel country, is a wild and rugged region, a continuation of the Khattak hills.
[2] The tehsil derives its name from the Isa Khel tribe, sub-tribe of the Niazi Afghans, who, settling here during the sixteenth century, long maintained their independence of the Mughal empire, and at last succumbed to the Nawab of Dera Ismail Khan.