square mile
Various units of area, with square mile being represented as a yellow square
General information
Unit systemImperial, United States customary units
Unit ofarea
Symbolmi2, sq mi
1 mi2 in ...... is equal to ...
  • 4.0145×109 sq in
  • 2.7878×107 sq ft
  • 3.0976×106 sq yd
  • 640 acres
   SI units   
  • 2.59×106 m2
  • 2.59 km2

The square mile (abbreviated as sq mi and sometimes as mi2)[1] is an imperial and US unit of measure for area. One square mile is equal to the area of a square with each side measuring a length of one mile.[2]


One square mile is equal to:

One square mile is also equivalent to:

Similarly named units

Miles square

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.


  1. ^ Rowlett, Russ (September 1, 2004). "S", How Many? A Dictionary of Units of Measurement. University of North Carolina at Chapel Hill. Retrieved February 22, 2012.
  2. ^ Davies, Charles (1872). Mathematical dictionary and cyclopedia of mathematical science. Original from Harvard University: A.S. Barnes and co. p. 582.
  3. ^ François Cardarelli (2003). Encyclopaedia of scientific units, weights, and measures: their SI equivalences and origins. Springer. p. 3. ISBN 978-1-85233-682-0. Retrieved 22 February 2012.