A bailiwick is the area of jurisdiction of a bailiff. The term was also applied to a territory in which the sheriff's functions were exercised by a privately appointed bailiff under a royal imperial writ. The word is now more generally used in a metaphorical sense, to indicate a sphere of authority, experience, activity, study, or interest.

At Bicester in Oxfordshire the lord of the manor of Market End was the Earl of Derby who in 1597 sold a 9,999 year lease to 31 principal tenants. This in effect gave the manorial rights to the leaseholders, ‘purchased for the benefit of those inhabitants or others who might hereafter obtain parts of the demesne’. The leaseholders elected a bailiff to receive the profits from the bailiwick, mainly from the administration of the market and distribute them to the shareholders. From the bailiff’s title the arrangement became known as the Bailiwick of Bicester Market End. By 1752 all of the original leases were in the hands of ten men, who leased the bailiwick control of the market to two local tradesmen.

The term originated in France (bailie being the Old French term for a bailiff). Under the ancien régime in France, the bailli was the king's representative in a bailliage, charged with the application of justice and control of the administration. In southern France, the term generally used was sénéchal (cf seneschal) who held office in the sénéchaussée. The administrative network of baillages was established in the 13th century, based on the earlier medieval fiscal and tax divisions (the 'baillie') which had been used by earlier sovereign princes. (For more on this French judicial system, see bailli, prévôt and Early Modern France.)

A bailiwick () was also the territorial division of the Teutonic Order.

In English, the original French bailie was combined with '-wic', the Anglo-Saxon suffix meaning a village, to produce a term meaning literally 'bailiff's village' - the original geographic scope of a bailiwick. In the 19th century, it was absorbed into American English as a metaphor for one's sphere of knowledge or activity.

The term survives in administrative usage in the British Crown dependencies of the Channel Islands, which for administrative purposes are grouped into the two bailiwicks of Jersey (comprising the island of Jersey and uninhabited islets such as the Minquiers and Écréhous) and Guernsey (comprising the islands of Guernsey, Sark, Alderney, Brecqhou, Herm, Jethou and Lihou). Each Channel Island bailiwick is headed by a Bailiff.

Bailiwick is also used in computer DNS terminology to reference the area of control a domain has over subdomain name spaces. For example: www.google.com, 1.google.com, 2.google.com are all in the bailiwick google.com, but www.ebay.com and www.google.com are different bailiwicks.

Category:Administrative divisions
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