Furlong is a unit of length in the inch-pound system of measurement that is customarily used in the United States. One furlong equals 40 rods, or 1/8 mile (0.202 kilometer).
Furlong originally meant the length of a furrow in a plowed field. However, this meaning was indefinite because farmers plowed furrows of many different lengths. Gradually, the furlong became a standard length. Among Old English writers, the furlong was 1/8 mile in any of the world’s different standards for a mile. Today, the furlong is used mainly to measure distances in horse races.
