Square Mile (mi²)

US & ImperialCurrent unit

640 acres or about 2.59 km². Used for the area of cities, states and countries in the US and UK.

1 square mile = 2,589,988.11 square meters (approximately).

About the square mile

A thousand Roman paces, mille passus, became the mile, and under Elizabeth I Parliament fixed the statute mile at eight furlongs, or 5,280 feet, in place of the older Roman-based value. The square mile inherits that length. Its most famous use came in the United States: the Land Ordinance of 1785 started the Public Land Survey System so that western land could be surveyed and sold to pay war debts, beginning with the Seven Ranges in eastern Ohio.

In that system a section is roughly one square mile, or 640 acres, and a township is 36 sections in a square six miles on a side. One square mile is nearly 2.59 million square meters. Chicago's Midway International Airport, at about 650 acres, covers roughly 1.02 square miles. Beware the phrase mile square: a region 20 miles square has 400 square miles, but so does a rectangle 10 by 40 miles. The US survey version of the mile was retired from 1 January 2023, but the international square mile remains the unit for cities, states and countries in the US and UK.

Sources: Wikipedia: Square mile; Wikipedia: Public Land Survey System; Wikipedia: Mile

Square Mile conversion chart

1 square mile expressed in every other area unit:

More US & Imperial units

• square inch (area)
• square foot (area)
• square yard (area)
• acre (area)
• square rod (area)
• square chain (area)
• inch (length)
• foot (length)
• yard (length)
• mile (length)
• thou (length)
• league (length)
• furlong (length)
• chain (length)
• rod (length)
• link (length)

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