The square mile is an imperial and US unit of area equal the area of a square of one statute mile. It should not be confused with miles square, which refers to the number of miles on each side squared. For instance, 20 miles square (20×20 miles) is equal to 400 square miles.
|1 square mile||=640 acres|
|=27,878,400 square feet|
|=2.589988110336 square kilometers (exactly)|
In the Public Land Survey System of the U.S. and the Dominion Land Survey of Canada, the size of a standard section of land is one square mile, but always with the marginally larger survey definition.