The square mile (abbreviated as sq mi and sometimes as mi2) is an imperial and US unit of measure for area. One square mile is an area equal to the area of a square with sides of length one mile.
One square mile is equal to:
One square mile is also equivalent to:
Square miles should not be confused with miles square, a square region with each side having a length of the value given. For example, a region which is 20 miles square (20 mi × 20 mi) has an area of 400 sq mi; a rectangle of measuring 10 mi × 40 mi also has an area of 400 sq mi, but is not 20 miles square.
In the United States Public Land Survey System, "square mile" is an informal synonym for section.