Square Mile to Square Mile (US Survey) Converter
Unit Converter
Instant · Precise · Universal
23 units available
6 categories total
How to Convert Square Mile to Square Mile (US Survey)
To convert mi² to km²: multiply by 2.59. To acres: multiply by 640. To hectares: multiply by 259.
1 mi² = 640 acres = 27,878,400 ft² = 2.59 km² = 259 ha.
For example, 1 Square Mile (mi²) = 0.999996 Square Mile (US Survey) (mi² (US)).
Square Mile to Square Mile (US Survey) — Common Values
| Square Mile (mi²) | Square Mile (US Survey) (mi² (US)) |
|---|---|
| 0.1 | 0.0999996 |
| 0.5 | 0.499998 |
| 1 | 0.999996 |
| 2 | 1.999992 |
| 5 | 4.99998 |
| 10 | 9.99996 |
| 25 | 24.9999 |
| 50 | 49.9998 |
| 100 | 99.9996 |
| 500 | 499.998 |
| 1000 | 999.996 |
About Square Mile (mi²)
Definition
The square mile is an imperial unit of area equal to the area of a square with sides of one mile (2.59 km²).
Mathematical Relationship
1 mi² = 640 acres = 27,878,400 ft² = 2.59 km² = 259 ha.
Conversion Formula
To convert mi² to km²: multiply by 2.59. To acres: multiply by 640. To hectares: multiply by 259.
Practical Applications
City areas, county sizes, population density, land surveys, and geographic comparisons.
Interesting Facts
Manhattan is about 22.8 mi². The state of Texas is 268,596 mi². Rhode Island (smallest US state) is 1,214 mi².
Common Mistakes
1 mi ≈ 1.609 km, but 1 mi² ≈ 2.59 km² (not 1.609). Area conversion squares the factor.
Educational Tips
1 mi² = 640 acres. This 'section' (640 acres) is the basis of the US Public Land Survey System grid.
About Square Mile (US Survey) (mi² (US))
Definition
The US survey square mile is a historical area unit based on the US survey foot, equal to approximately 2,589,998.47 m².
Mathematical Relationship
1 mi² (US) ≈ 2,589,998.47 m². Differs from international mi² (2,589,988.11 m²) by about 10.36 m².
Conversion Formula
To convert US survey mi² to km²: multiply by 2.590. To international mi²: multiply by ~1.000004.
Practical Applications
Historical US Public Land Survey System sections (each nominally 1 mi² US survey).
Interesting Facts
Over one square mile, the US survey definition differs from the international definition by about 10.4 m² — roughly a 3 m × 3.5 m room.
Common Mistakes
Using the US survey mile for new calculations. Deprecated since 2023 — use the international definitions.
Educational Tips
The US Survey system was a legacy from 1893. Its 2023 retirement unified US measurements with the international standard.