Convert Square Mile (US Survey) (mi² (US)) to Acre (ac) instantly.
About these units
Square Mile (US Survey) (mi² (US))
The US survey square mile is extremely close to the international square mile but is defined using the US survey foot, a slightly different value than the international foot historically used in land surveying. This unit appears in American land deeds, cadastral maps, and federal land management documents. The Public Land Survey System (PLSS), which divided much of the western United States into townships and sections, relied heavily on survey-based square miles. Although the modern US has transitioned to the international foot (as of 2023), historical land descriptions remain legally tied to the survey-based definition, ensuring its continued relevance.
Acre (ac)
An acre is a traditional Anglo-American land unit equal to 43,560 square feet, or roughly 4,047 m². It originated from medieval English farming, where an acre represented the amount of land a yoke of oxen could plow in one day—reflecting its deep agricultural roots. The acre remains widely used in the United States and the UK (in certain contexts), especially in real estate, agriculture, and land conservation. It is culturally intuitive for rural populations, where land plots have been measured in acres for centuries. The unit's longevity demonstrates how historical agricultural practices shaped modern land evaluation systems. Despite its lack of coherence with the metric system, the acre endures because of its cultural familiarity and long-standing legal integration.