link
The length of one joint of Gunter's chain, being the hundredth part of it, or 7.92 inches, the chain being 66 feet in length.
link: a chain segment that measures exactly 7.92 inches
A link is a single rigid segment of Gunter's chain, a measuring instrument that has been standard in land surveying for over three centuries. The chain itself is 66 feet long and consists of exactly 100 links connected end to end, making each link precisely 7.92 inches. This uniform subdivision allows surveyors to measure distances and record them in chains and links, a notation that persists in property deeds and boundary descriptions across North America.
Each link is typically made from iron or steel wire bent into a small loop and welded or brazed to the next. The loops are sized to sit flat against each other when the chain lies straight, minimizing kinks during measurement. The weight and construction mean Gunter's chain can be laid along the ground, stretched taut, and read directly without calculation, making it faster than converting imperial measurements to decimal fractions on site.
Why this peculiar length?
The 66-foot length was chosen because it divides neatly into 10 square chains per acre, a relationship that simplifies conversion between linear and area measurements. A chain of 66 feet, when squared, equals 43,560 square feet, which is exactly one acre. This makes calculations in the field straightforward: if you measure a rectangular parcel as 10 chains by 10 chains, you immediately know it is 10 acres without arithmetic.
The link unit persists in legal descriptions of property even as electronic distance measurement has replaced physical chains on most modern surveys. Older deeds specify boundaries in chains and links, and these measurements appear in property records, building surveys, and historical maps. Understanding the term is essential for anyone interpreting nineteenth and twentieth century surveying documents or working with rural property boundaries that have never been resurveyed in metric or decimal feet.
Gunter's chain has been largely superseded by steel tapes and electronic distance meters, but the unit remains embedded in land records, making the link a legacy measurement that surveyors still need to recognize and occasionally convert when dealing with historical data or jurisdictions that retain traditional notation.