How Deep Is a League?

In English-speaking countries, one league is equal in 3 miles. Historically, the length of a mile has been defined variously based upon place and time, but as a measure of ocean depth, as of 2014, one league is 3 nautical miles or 18,228 feet.

The league was originally a unit of measurement used by the Gauls of Europe. It originally referred to the length a person could walk in an hour. The Romans defined this length as 1,500 paces or 1.5 Roman miles. The mile and the league have been closely linked ever since. Differences in what length was meant by a league varied by country, time period, and whether the units were used to measure distance on land or at sea. Perhaps due to its imprecision, the league is no longer used as an official unit of measurement by any country.