The City of Westminster was established as a borough in 1965 by the amalgamation of the boroughs of Westminster. City of Westminster, inner borough of London, England. It lies on the north bank of the River Thames at the heart of London’s West End. The City of Westminster is flanked to the west by Kensington and Chelsea and to the east by the City of London. It contains the most famous sites in London. Some of the popular tourist sites are Buckingham Palace, the Palace of Westminster, Big Ben and nearby Westminster Abbey.