Kalihati upazila on the north, Mirzapur and Delduar upazilas on the south, Sakhipur upazila on the east Delduar and Tangail Sadar upazilas on the west.

Basail thana, now an upazila, was established in 1913. The upazila consists of six union parishads, 73 mouzas and 117 villages.

Basail Upazila is located in Tangail District. Upazilla(s)/Thana(s) in Tangail are Basail Upazila, Bhuapur Upazila, Delduar Upazila, Ghatail Upazila, Gopalpur Upazila, Kalihati Upazila, Madhupur Upazila, Mirzapur Upazila, Nagarpur Upazila, Sakhipur Upazila, Tangail Sadar Upazila.