Convert Square Miles to Hectares (mi2 to ha)
1 square mile (mi²) = 258.998811 hectares (ha). 1 ha = 0.003861021585 mi². Example: 15 mi² = 15 × 258.998811 = 3884.982166 ha.
Also searched as square miles to ha, square miles in ha, square miles into hectares, mi2 to ha, mi2 in hectares, mi2 into hectare, square mile to hectare, mi2 to hectares converter and how many hectares in a square mile.
1 mi² = 258.998811 ha
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk square mile to hectare converter to paste a column from Excel.
How to Convert Square Mile to Hectare
- 1 mi² = 258.998811 ha
- 1 ha = 0.003861021585 mi²
- Example: convert 15 mi² to ha: 15 mi² = 15 × 258.998811 ha = 3884.982166 ha
Formula
ha = mi² × 258.9988110336
Derivation from SI units:
- 1 mi² = (1609.344 m)² = 2 589 988.110336 m² = 640 acres
- 1 ha = 100 m × 100 m = 10 000 m² (a non-SI unit accepted for use with the SI)
- 1 mi² = 2589988.110336 m² ÷ 10000 m² per ha = 258.9988110336 ha
Both units are defined exactly, so the factor is exact. Square Mile definition: square mile; Hectare definition: hectare.
Worked examples
- A reading of 2 mi² converts to 517.9976221 ha.
2 mi² × 258.998811 = 517.9976221 ha - A value of 25 mi² is 6474.970276 ha.
25 mi² × 258.998811 = 6474.970276 ha
Square Mile to Hectare conversion table
| Square Miles (mi²) | Hectares (ha) |
|---|---|
| 0.1 mi² | 25.8998811 ha |
| 0.5 mi² | 129.4994055 ha |
| 1 mi² | 258.998811 ha |
| 2 mi² | 517.9976221 ha |
| 5 mi² | 1294.994055 ha |
| 10 mi² | 2589.98811 ha |
| 25 mi² | 6474.970276 ha |
| 50 mi² | 12949.94055 ha |
| 100 mi² | 25899.8811 ha |
| 1000 mi² | 258998.811 ha |
Where it's used
Square Miles are used for US city and county areas, while hectares appear in farm and forest land. Both measure area, so the conversion is a fixed factor.
Square Mile to other area units
| Conversion | 1 mi² equals |
|---|---|
| square mile to hectare | 258.998811 ha |
| square mile to square meter | 2589988.11 m² |
| square mile to square centimeter | 25899881100 cm² |
| square mile to square foot | 27878400 ft² |
| square mile to square inch | 4014489600 in² |
| square mile to acre | 640 ac |
| square mile to square millimeter | 2589988110000 mm² |
| square mile to square kilometre | 2.58998811 km² |
Show 1 more units
| square mile to square yard | 3097600 yd² |
|---|
Frequently asked questions
How many hectares are in 1 square mile?
1 mi² = 258.998811 ha.
How do I convert square miles to hectares?
Multiply the value in mi² by 258.998811. For example, 15 mi² × 258.998811 = 3884.982166 ha.
Is the mi² to ha conversion exact?
Yes. Both units are defined exactly, so the ratio is exact; its decimal form does not terminate and is shown here to 10 significant figures (more with the precision selector).
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "square mile (mi²)".
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 8, non-SI units accepted for use with the SI.
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert Square Miles to Hectares (mi2 to ha). Retrieved October 25, 2026, from https://scientificconverters.com/area/square-miles-to-hectares/
IEEE
Scientific Converters, "Convert Square Miles to Hectares (mi2 to ha)," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/area/square-miles-to-hectares/