Police division

A division was the usual term for the largest territorial subdivision of most British police forces. In major reforms of police organisation in the 1990s divisions of many forces were restructured and retitled Basic Command Units (BCUs), although some forces continue to refer to them as divisions.
The term was and used in many other countries of the British Empire and Commonwealth.
United Kingdom.
The term has existed since the creation of police forces in the early 19th century. Most police forces were divided into divisions, usually commanded by a Superintendent. These could cover a wide rural area, a substantial town, or a portion of a city, depending on the population (London, for instance, was divided at one point into 67 Metropolitan Police divisions and a further four City of London Police divisions). In 1949, the Metropolitan Police regraded its divisional commanders as Chief Superintendents and most other forces followed suit.
Divisions were usually divided into Sub-Divisions, commanded by Inspectors (or, in the Metropolitan Police, Sub-Divisional Inspectors, a higher rank). Some rural forces did not acquire this further organisational level until well into the 20th century, however. Sub-divisional commanders were later regraded as Chief Inspectors in most forces. In London, divisions were later grouped together as districts, each commanded by a Chief Constable and later a Deputy Assistant Commissioner.
With the reforms of the 1990s sub-divisions, as well as divisions, acquired a variety of new names.
Hong Kong.
The Hong Kong Police Force divides its territory into 23 divisions or districts, each reporting to one of the six regions.
India.
In India, the equivalent to a division is a Police District. Policing in India is on a state basis, and every state is divided into a number of districts. Each district is headed by a Superintendent of Police. The district is subdivided into Sub Divisions, each commanded by a Deputy Superintendent of Police. Sub Divisions are further divided into Police Circles. In the case of a district including large cities, two separate police districts are created, known as the City Police District, headed by a Commissioner, and the Rural District Police, headed by a Superintendent.
Republic of Ireland.
In the Republic of Ireland, the Garda Síochána divides its operational area into 23 divisions, which in turn report to one of six regions. Most, but not all of these divisions, are aligned to county borders. Each division is commanded by a Chief Superintendent. Divisions are further divided into districts, commanded by a Superintendent.
Singapore.
The Singapore Police Force divides the city-state into seven divisions of varying physical sizes and population. These boundaries tend to be demarcated in terms of cases handled by observing criminal trends over time, instead of being based on area or population sizes alone.
Canada.
A few police departments in Canada use divisions to represent stations or patrol areas, but some are a mix of operational and administrative units with the force.
A few police agencies using divisions include: