Convert Square Mile (mi²) to Square Chain (ch²) 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 Chain (ch²)
A square chain equals the area of a square one chain (~66 feet) per side, resulting in 4,356 square feet, or exactly 1/10 of an acre. This unit is closely linked to the chain, a surveyor's unit standardized by Edmund Gunter in the 17th century. Because 10 square chains make an acre, survey calculations for early colonial and American lands were extremely efficient. Square chains allowed surveyors to map and divide land rapidly using ropes or metal chains, producing a legacy seen in long, straight property lines still visible today across rural landscapes.