Convert Chain (ch) to Mile (US Survey) (mi (US)) instantly.
About these units
Chain (ch)
A chain is equal to 66 feet or 4 rods, and it was standardized by surveyor Edmund Gunter in the 17th century. "Gunter's chain," consisting of 100 metal links, became the backbone of land surveying in the English-speaking world for centuries. Its convenience stems from simple arithmetic: 10 square chains make an acre, making land area calculations straightforward. Railroads, farmland, and city parcels across the United States and the Commonwealth nations were once laid out using chains, so the unit appears in countless historical records. Even today, some legal property descriptions still reference chain-based measurements, making the unit relevant for modern surveyors who interpret old maps. Although high-precision digital equipment has replaced physical chains, the unit's structural role in land division ensures its lasting importance.
Mile (US Survey) (mi (US))
The US Survey Mile equals 5,280 US Survey Feet (~1,609.347 meters). Slightly longer than the international mile due to the use of the US survey foot, it has been essential for mapping, transportation planning, and geodetic calculations in the United States. Surveyors and engineers relied on the US survey mile to ensure precise alignment of property boundaries, railroad tracks, and infrastructure projects. Over long distances, even small differences between the US survey and international mile can accumulate significantly, necessitating care in measurement. Though the international mile is now standard, the US survey mile remains important for interpreting historical maps, legal descriptions, and older engineering plans.