| Furlong | |
|---|---|
| Unit system | imperial/US units |
| Unit of | length |
| Conversions | |
| 1 furlong in ... | ... is equal to ... |
| imperial/US units | 220 yd or 1⁄8 mi |
| metric (SI) units | 201.1680 m |
- The rod is a historical unit of length equal to 5+1⁄2 yards. It may have originated from the typical length of a mediaeval ox-goad. There are 4 rods in one chain.
- The furlong (meaning furrow length) was the distance a team of oxen could plough without resting. This was standardised to be exactly 40 rods or 10 chains.
- An acre was the amount of land tillable by one man behind one team of eight oxen in one day. Traditional acres were long and narrow due to the difficulty in turning the plough and the value of river front access.
- An oxgang was the amount of land tillable by one ox in a ploughing season. This could vary from village to village, but was typically around 15 acres.
- A virgate was the amount of land tillable by two oxen in a ploughing season.
- A carucate was the amount of land tillable by a team of eight oxen in a ploughing season. This was equal to 8 oxgangs or 4 virgates.
A furlong is a measure of distance in imperial units and United States customary units equal to one-eighth of a mile, equivalent to any of 660 feet, 220 yards, 40 rods, 10 chains, or approximately 201 metres. It is now mostly confined to use in horse racing, where in many countries[which?] it is the standard measurement of race lengths, and agriculture, where it is used to measure rural field lengths and distances.
In the United States, some states use older definitions for surveying purposes, leading to variations in the length of the furlong of two parts per million, or about 0.4 millimetres (1⁄64 inch). This variation is small enough to not have practical consequences in most applications.
Using the international definition of the yard as exactly 0.9144 metres, one furlong is 201.168 metres, and five furlongs are about 1 kilometre (1.00584 km exactly).