The square mile, unit of area
The square mile is exactly 2 589 988.110336 square meters, or 640 acres, or 2.59 square kilometers. It is a unit of country rather than of parcel, used for towns, watersheds and population densities.
The United States was drawn on it. The Land Ordinance of 1785 ordered the western territory surveyed into townships of six miles by six, each holding thirty-six sections of one square mile, each section being 640 acres. That grid is why so many rural American roads run straight for a mile and then turn a right angle, and why the standard homestead claim was a quarter section, 160 acres. The pattern is still visible from the air over the Midwest, more than two centuries later.
The square mile in other units
| 1 mi² | 2.58999 km² |
| 1 mi² | 258.999 ha |
| 1 mi² | 25,900 a |
| 1 mi² | 2,589,988 m² |
| 1 mi² | 25,899,881,103 cm² |
| 1 mi² | 640 ac |
| 1 mi² | 27,878,400 ft² |
| 1 mi² | 4,014,489,600 in² |
| 1 mi² | 3,097,600 yd² |
| 1 mi² | 2,589,988,110,336 mm² |
| 1 mi² | 2,590 dunum |
| 1 mi² | 783,471 tsubo |
| 1 mi² | 616.664 feddan |
| 1 mi² | 1,619 rai |
| 1 mi² | 783,471 pyeong |
| 1 mi² | 14,800 qirat |
| 1 mi² | 25,600 guntha |
| 1 mi² | 64,000 cent |
| 1 mi² | 5,120 kanal |
Frequently asked questions
How many acres are in a square mile?
640 exactly, which is what makes the acre and the square mile fit together so neatly in American land records. A quarter section is 160 acres and a forty is a quarter of that.
How many square kilometers is a square mile?
2.589988110336 exactly, so roughly two and six tenths. The inverse is more useful in Europe: a square kilometer is 0.386 square miles.
Is a section the same thing as a square mile?
In the American public land survey, yes: a section is one square mile of the township grid. The word carries the survey with it, which is why a deed can describe a parcel by section, township and range without giving a single dimension.