What is square mile?
A square mile is a unit of area in imperial and US customary systems equal to 640 acres. It is used to express the size of cities, regions, and geographic territories in the United States and United Kingdom.
Real-world uses
Square miles are used for city areas, county sizes, and population density calculations in the US and UK. Manhattan is about 23 square miles. National parks and wilderness areas are often described in square miles in American contexts.
History
The square mile became a standard geographic unit in English-speaking countries alongside the statute mile. The US Public Land Survey System, established in 1785, divided territory into 36-square-mile townships, each containing 36 one-square-mile sections.
Common mistakes
Assuming 1 square mile = 1 mile × 1 mile = 1 mi². While correct, people forget that 1 sq mi = 640 acres or about 2.59 km², leading to errors when comparing American and metric area figures.
What is hectare?
A hectare is a metric unit of area equal to 10,000 square metres. It is the standard unit for measuring agricultural land, forest areas, and large parcels of real estate in metric countries.
Real-world uses
Hectares are the standard unit for agricultural land measurement, forestry management, and urban planning worldwide. Wine regions report vineyard sizes in hectares, and environmental reports quantify habitat loss in hectares. One hectare is roughly the size of two American football fields.
History
The hectare was introduced during the French Revolution as part of the metric system, originally called a "hecto-are" (100 ares). Though not an official SI unit, it is accepted for use with SI and remains the predominant land area unit in global agriculture.
Common mistakes
Confusing hectares with acres—1 hectare is about 2.47 acres, not 1-to-1. Also, some people confuse "hectare" with "hectometre," but a hectare is 10,000 m² (100 m × 100 m), a unit of area, not length.
When is this conversion used?
Converting between square mile and hectare is common when working across metric and imperial systems, such as international trade, travel between countries with different measurement standards, or following instructions from a different region.
Worked examples
1 square mile = 258.99881103 hectare
1 hectare = 10,000 square metre
How to convert square mile to hectare
To convert square mile to hectare, multiply the value by 258.99881103.
To convert hectare back to square mile, multiply by 0.00386102.
Measurement standards
The square metre is the SI derived unit of area. The hectare (10,000 m²) is accepted for use with the SI by the BIPM, particularly for land measurement, though it is not an SI unit itself.
Did you know?
Vatican City, the world's smallest independent state, covers just 0.44 km² (about 109 acres) — smaller than many golf courses. By contrast, Russia spans over 17.1 million km², nearly 39 million times larger.
Quick reference: square mile to hectare
| square mile | hectare |
|---|---|
| 0.1 | 25.8998811 |
| 0.5 | 129.49940552 |
| 1 | 258.99881103 |
| 2 | 517.99762207 |
| 5 | 1,294.99405517 |
| 10 | 2,589.98811034 |
| 25 | 6,474.97027584 |
| 50 | 12,949.94055168 |
| 100 | 25,899.88110336 |
| 250 | 64,749.7027584 |
| 500 | 129,499.4055168 |
| 1,000 | 258,998.8110336 |
Common values
| square mile | hectare | |
|---|---|---|
| A4 paper | 2.393833e-08 square mile | 0.0000062 hectare |
| Parking space | 0.00000483 square mile | 0.00125 hectare |
| Tennis court | 0.00010072 square mile | 0.026087 hectare |
| Football field (soccer) | 0.00275677 square mile | 0.714 hectare |
| Central Park, NYC | 1.31660836 square mile | 341 hectare |