Furlong the fundamental unit of land measurement. A furlong was forty rods, an acre four by 40 rods, or four rods by one furlong, and thus 160 square rods. At the time, the Saxons used the North German foot, which was 10 percent longer than the foot of today. When England changed to the shorter foot in the late 13th century, rods and furlongs remained unchanged, since property boundaries were already defined in rods and furlongs. The only thing that changed was the number of feet and yards in a rod or a furlong, and the number of square feet and
Furlong United Kingdom, which define the furlong in terms of the international yard of exactly 0.9144 metres, a furlong is 201.168 m. Australia does not formally define the furlong, but it does define the chain and link in terms of the international yard. In the United States, which defines the furlong, chain, rod, and link in terms of the U.S. survey foot of exactly metre, a furlong is approximately 201.1684 m long. The United States does not formally define a "survey yard". The difference of approximately two parts per million between the U.S. value and the "international" value is insignificant for