The City and Liberty of Westminster was a unit of local government in the county of Middlesex, England.

The area now forms the southern part of the City of Westminster in Greater London.

The Penny Cyclopaedia in 1843 describes the boundaries as: formed on the southern and chief part of the eastern side by the left bank of the river Thames.

The boundary leaves the river about midway between Waterloo bridge and Hungerford market, and with a little deviation follows the course of the Strand eastward to Temple Bar, being separated from the river in this part by what is termed the liberty of the duchy of Lancaster and by the western part of the Temple.

The northern boundary runs in a very direct line westward along Oxford Street and the north side of Hyde Park and Kensington Gardens, making a small detour in one place, so as to include St. George’s burying-ground, to the northern end of the Serpentine river.