Convert Square Mile (mi²) to Square Kilometer (km²) instantly.
About these units
Square Mile (mi²)
A square mile equals 640 acres or about 2.58999 km². It is the primary unit for describing large areas in the United States and the UK, particularly in geography and land-use planning. City sizes, county boundaries, national park dimensions, and lake surfaces are often expressed in square miles. Because of its large scale, it is ideal for measuring political subdivisions, conservation zones, and territorial claims. The square mile also appears in demographic statistics—such as population density—and in historical surveys of American frontiers, where square-mile sections formed the backbone of land distribution policies.
Square Kilometer (km²)
A square kilometer equals one million square meters and is the standard unit for expressing large land areas, especially in geography, ecology, national planning, and environmental science. Countries, cities, national parks, forests, wetlands, and even ocean surface regions are frequently described in km². Because it provides a manageable scale for features too large for hectares or acres, it is widely used in atlases, scientific papers, and government reports. The square kilometer also plays a major role in ecology, where species ranges, habitat fragmentation, and conservation zones are measured using this unit. In geopolitics, km² help define national borders and territorial claims, making it a powerful instrument of scientific and political discourse.