How Big Is London?

London was founded on the bank of the River Thames by the Romans in 50 AD. It was originally named Londinium, from which its modern name was derived. The ancient part of the city is about 1.12 square miles and is known as "the City of London." From here, London grew to become the most populous city in Europe from 1831 to 1925.

As of 2014, about 12.5 percent of the United Kingdom's population lives in London. Its metropolitan area is 3,236.31 square miles and boasts a population of 15,010,295, making it the largest metropolitan area in the European Union.