Commonly used as an alternative for the City of London, the term ‘Square Mile’ comes from the amount of land in the heart of the city which is under the jurisdiction of the City of London Corporation.
The City (with a capital ‘c’, it’s another commonly used term for the City of London) contains the core of the ancient city which has stood here since Roman times and is still the financial centre of the city. While called the ‘Square Mile’, it actually encompasses 1.12 square miles (equivalent to 716.80 acres or 2.90 square kilometres).
While the City has been roughly that size since medieval times (the City has long included land both within the medieval city walls as well as some without), the term ‘Square Mile’ is understood to have been a relatively recent invention, created in the Victorian era.
It’s interesting to note that the Square Mile was slightly smaller – just 1.05 square miles – up until the mid-1990s when some boundary changes increased it to its current size.
Below is a map showing the outline of the ‘Square Mile’ today…