平方英里（简写：sq. mi or mi²）是一个面积单位。

1 平方英里等于：

• 4,014,489,600 平方英寸
• 27,878,400 平方英尺
• 2,589,998.11 平方米
• 640 英亩
• 2.589988110336 平方公里
• 3,097,600 平方码

The square mile (abbreviated as sq mi and sometimes as mi) 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; an area of 10 × 40 miles is likewise 400 square miles, but it is not 20 miles square.