Police district is a form of division of a geographical area patrolled by a police force. The 1885 Encyclopædia Britannica stated:
The determination of the geographical area of a police district is necessarily governed by a variety of circumstances. Physical features have sometimes to be taken into account as affecting the demarcations of intercourse, more frequently the occupations of the people and the amount of the population. A district may be too confined or too large for police purposes. The limited ideas of simple-minded rustics of a former generation whose views of complete independence consisted in inhabiting two adjacent rooms in different parishes, so as to effectually baffle the visits of parochial officers, is probably a notion of the past; but obstructions of a like kind may arise from too narrow boundaries. On the other hand dense populations or long-accustomed limits may outweigh convenience arising from a wide area. In any case the making of altogether new boundaries merely for police purposes is very undesirable. The county, or divisions of a county or city, or the combination of parishes, ought to be and are sufficient for determining the boundaries of a police district.
Police forces using this format include: