A borough is an administrative division in various countries. In principle, the term borough designates a self-governing township although, in practice, official use of the term varies widely.
The word borough derives from common Germanic *burg, meaning fort: compare with bury (England), burgh (Scotland), Burg (Germany), borg (Scandinavia), burcht (Dutch) and the Germanic borrowing present in neighbouring Indo-european languages such as borgo (Italian), bourg (French) and burgo (Spanish and Portuguese). The incidence of these words as suffixes to place names (for example, Canterbury, Strasbourg, Luxembourg, Edinburgh, Hamburg, Gothenburg) usually indicates that they were once fortified settlements.
In the Middle Ages, boroughs were settlements in England that were granted some self-government; burghs were the Scottish equivalent. In medieval England, boroughs were also entitled to elect members of parliament. The use of the word borough probably derives from the burghal system of Alfred the Great. Alfred set up a system of defensive strong points (Burhs); in order to maintain these settlements, he granted them a degree of autonomy. After the Norman Conquest, when certain towns were granted self-governance, the concept of the burh/borough seems to have been reused to mean a self-governing settlement.
The concept of the borough has been used repeatedly (and often differently) throughout the English-speaking world. Often, a borough is a single town with its own local government. However, in some cities it is a subdivision of the city (for example, London, New York City, Montreal, and Tokyo). In such cases, the borough will normally have either limited powers delegated to it by the city's local government, or no powers at all. At certain times, London has had no overall city government and boroughs were the main unit of local government for Londoners; in Tokyo, they are known as wards or cities, and have city status, but these still form parts of a larger municipal government which has merged with that of the prefecture. In other places, such as Alaska, borough designates a whole region; Alaska's largest borough, the North Slope Borough, is comparable in area to the entire United Kingdom. In Australia, borough can designate a town and its surrounding area, such as the Borough of Queenscliffe.
Boroughs as administrative units are to be found in Ireland and the United Kingdom, more specifically in England and Northern Ireland. Boroughs also exist in the Canadian province of Quebec and formerly in Ontario, in some states of the United States, in Israel, and formerly in New Zealand.