Furlong: traditional unit of distance

Characteristics and relationships

The furlong is tied to several other traditional measures that made land calculation practical in pre‑metric economies. Key relationships include:

• 1 furlong = 660 feet (201.168 metres)
• 1 furlong = 40 rods (also called poles or perches)
• 1 furlong = 10 chains (a chain is 66 feet)
• 8 furlongs = 1 mile

History and origin

The word furlong comes from Old English elements meaning "furrow" and "long": it originally described the length of a furrow in a cultivated field. Medieval agrarian practice used the furlong together with a narrow strip width (the chain) to define an acre — historically, an acre was the area of land one chain wide by one furlong long. The chain used for surveying (Gunter's chain) was popularized in the 17th century and helped standardize these relationships for mapping and property description.

Modern uses and examples

Although largely superseded by metric units for most scientific and everyday purposes, the furlong persists in a few areas. Horse racing commonly expresses race distances in furlongs, and older legal deeds, land records and some surveying traditions still reference furlongs, chains and rods. As a rough example, a six‑furlong race equals three‑quarters of a mile.

Notable facts and distinctions

The furlong illustrates how agricultural practice shaped measurement systems: units were chosen for convenience in ploughing and estate layout rather than abstract standardization. Today it remains a useful historical and practical term in contexts that preserve traditional English‑language measurements.

For more detailed historical or technical discussion consult sources on traditional units and surveying practice such as texts on the unit systems and historical metrology (distance measures), or guides to the imperial and US customary systems; comparisons with the mile are especially common.