A unit of length is a way of measuring length or distance.
Common units of length in the International System of Units (SI) are:
Non-SI units of length include:
Common Imperial units and U.S. customary units of length include:
In addition, the following are used by mariners...
...and surveyors in the United States continue to use...
...while horse racing keeps alive:
Astronomical measure uses:
Physics also uses:
Archaic units of distance are described in the article on Ancient weights and measures. They include:
