- This article is about the unit of measure. In England, the Square Mile is a traditional name for the City of London.
A square mile (symbol sq. mi or mi² or sq. mile, sometimes sq. m. although this can be confused with square metre) is an imperial unit which is the area of a square whose side is one mile (or 5,280 feet). A square mile is equal to 27,878,400 square feet, 640 acres, or roughly 2½ square kilometres (2.589988 km², to be more exact). In the Public Land Survey System of the US and the Dominion Land Survey of Canada, the size of a standard section of land is one square mile. Note that the abbreviation sq. remains common with miles or an abbreviated form; the use of a superscript 2 to indicate a squared unit is more common with metric units, so even in measurements expressed in dual units the use of "sq. mi" and "kmē" together is often seen..