Square Mile to Acre (US Survey) Converter
Unit Converter
Instant · Precise · Universal
23 units available
6 categories total
How to Convert Square Mile to Acre (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) = 639.99744 Acre (US Survey) (ac (US)).
Square Mile to Acre (US Survey) — Common Values
| Square Mile (mi²) | Acre (US Survey) (ac (US)) |
|---|---|
| 0.1 | 63.999744 |
| 0.5 | 319.99872 |
| 1 | 639.99744 |
| 2 | 1279.99488 |
| 5 | 3199.9872 |
| 10 | 6399.9744 |
| 25 | 15999.936 |
| 50 | 31999.872 |
| 100 | 63999.744 |
| 500 | 319998.72 |
| 1000 | 639997.44 |
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 Acre (US Survey) (ac (US))
Definition
The US survey acre is a historical unit of area based on the US survey foot, equal to approximately 4,046.873 m².
Mathematical Relationship
1 US survey acre ≈ 4,046.873 m². Differs from international acre (4,046.856 m²) by about 0.016 m².
Conversion Formula
To convert US survey acres to m²: multiply by 4,046.873. To international acres: multiply by ~1.000004.
Practical Applications
Historical US land surveys, old property deeds, and State Plane Coordinate System calculations.
Interesting Facts
The difference between US survey and international acre is about 0.016 m² — roughly the area of a sheet of paper. Over large areas, it adds up.
Common Mistakes
Using US survey acre in new calculations — it's been deprecated since 2023. Use the international acre instead.
Educational Tips
As of 2023, the US survey foot and acre are retired. All US measurements now use the international definitions.