Convert Square Mile to Hectare (mi² → ha)

Converting square miles to hectares is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

1. 1
   Take your value in square miles

   Start with the number of square miles (mi²) you want to convert.
2. 2
   Multiply by 258.99881

   The conversion factor from mi² to ha is 258.99881. Multiply your value by this number.
3. 3
   Read the result in hectares

   The result is your value in hectares (ha).

Multiply the value in square miles by 258.99881. For the reverse direction, multiply by 0.003861.

• ✓1 mi² = 2.59 km² = 640 acres.
• ✓US land survey "section" = 1 mi²; "township" = 36 mi².
• ✓Common in US geography; replaced by km² in most of world.

• ✗Confusing square miles with statute miles (length).
• ✗Using 2.5 km² shortcut — correct 2.59 km² differs by 3.5%.
• ✗Mixing nautical square miles (irregular) with statute square miles.

What is the Square Mile?

The square mile equals exactly 2.589988110336 square kilometers (or 640 acres) and is the American unit for measuring large geographic areas: counties, states, watersheds, and large parks. The continental United States covers about 3 million square miles, and Texas alone is 268,597 mi². Population density in US contexts is given in people per square mile (e.g., New York City has about 27,000 people/mi²). The square mile relates to the acre (640 acres = 1 mi²), the square kilometer (1 mi² ≈ 2.59 km²), the square foot (1 mi² = 27,878,400 ft²), and the hectare (1 mi² ≈ 259 ha). It is the natural large-area unit for American geographic discussion, though metric countries use square kilometers for the same purpose.

• US states, counties and cities
• UK geographic and historical boundaries
• Large estate and national-park reporting in Anglo contexts

What is the Hectare?

The hectare equals exactly 10,000 square meters (100 m × 100 m) and is the international standard area unit for agricultural land, forestry, and large land development. Adopted as part of the metric system in 1795, the hectare's name combines 'hect-' (one hundred) with 'are' (the basic metric land unit of 100 m²) — meaning 100 ares. A standard FIFA football pitch covers about 0.7 hectares, and Central Park in New York is approximately 341 hectares. Farms across Europe, Latin America, Africa, and Asia are sized in hectares (a small family farm might be 5–20 ha). The hectare relates to the square meter (1 ha = 10,000 m²), the square kilometer (100 ha = 1 km²), the acre (1 ha ≈ 2.471 acres), and the square mile (1 ha ≈ 0.00386 mi²). It is one of the few non-SI units accepted for use with SI for legal land measurement.

• European farm, vineyard and orchard size
• Forestry and conservation land
• Large construction projects and urban development