The square mile (abbreviated as sq mi and sometimes as mi²) is an imperial and US unit of measure for an area equal to 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.

One square mile is equivalent to:

• 4,014,489,600 square inches
• 27,878,400 square feet
• 3,097,600 square yards
• 640 acres
• 258.9988110336 hectares
• 2560 roods
• 25,899,881,103.36 square centimetres
• 2,589,988.110336 square metres
• 2.589988110336 square kilometres

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