City of London
The City of London (informally known as the City or the Square Mile) is a city, ceremonial county and local government district in England. Established by the Romans around 47 AD as Londinium, it forms the historic centre of the wider London metropolis. Surrounded by the modern ceremonial county of Greater London, the City is a unique local authority area governed by the City of London Corporation, which is led by the Lord Mayor of London. It is included as part of the region of England governed by the Greater London Authority, which shares local government powers in the region with the councils of 32 London boroughs and the City of London Corporation.
Nicknamed the Square Mile, the City of London has an area of 1.12 sq mi (716.80 acres; 2.90 km2), making it the smallest city in the United Kingdom by area. It had a population of 8,583 at the 2021 census. Over 500,000 people were employed in the area as of 2019.
Together with Canary Wharf and the West End, the City of London forms the primary central business district of London, which is one of the leading financial centres of the world. The Bank of England and the London Stock Exchange are both based in the City. The insurance industry has a major presence in the area. The presence of the Inns of Court on the City's western boundary has made it a centre for the legal profession.
The present City of London constituted the majority of London from its settlement by the Romans in the 1st century AD to the Middle Ages, with only area within the City Wards
being considered London until urban expansion. It contains several historic sites, including St Paul's Cathedral, the Royal Exchange, Mansion House, Guildhall, the Old Bailey, Smithfield Market, the Monument to the Great Fire of London, and the remains of the ancient London Wall.