Thana an unit of police administration. Under a regulation issued on 7 November 1792 by the government of the Bengal Presidency, the district magistrates were asked to divide their respective districts into police jurisdictions called 'thana'. The area of a thana was not to exceed 'ten coss square'. Initially, a thana was purely a police jurisdiction headed by a junior police officer, namely the officer-in-charge (OC). With the creation of circle system, particularly after 1961, thana became the main centre of development activities with most of the development departments of the provincial government having their own functionaries at that level.

After 1982, each thana was upgraded into a upazila (sub-district) and the existing unit of administration, ie 'subdivision' was abolished based on the recommendations of committee for administrative reform/reorganisation (CARR) formed in early 1982 by the Ershad government. The principal functionary of an upazila was known as upazila nirbahi officer (UNO). In 1992, the upazila system was abolished and the post of UNO was transformed into thana nirbahi officer (TNO). Under the upazila system, the rank of the OC was upgraded into that of an inspector. The upazila system has since 1999 been revived. [AMM Shawkat Ali]