What Is a League?
A league (abbreviated lea) is an old unit of travel distance. In English use it is the land league of exactly 3 statute miles, which is 15,840 feet or 4,828.032 meters. It was never an SI or official international unit, and today it appears mainly in history, law and literature rather than in measurement.
The idea behind the league was time, not geometry: it was roughly the distance an average person or horse could travel in an hour. That made it practical before accurate maps, but it also meant the league varied from place to place. The Gaulish leuga used in Roman Gaul was 1.5 Roman miles, about 2.2 km. The French lieue changed several times, and a metric version was later fixed at 4 km. The Spanish legua was around 4.2 km, and Spanish land grants in colonial Texas were measured in square leagues of about 4,428 acres.
At sea, sailors used a marine league of 3 nautical miles, about 3.45 statute miles. This converter uses the English land league; if you are reading an older foreign source, check which league it means.
What Is a Mile?
The league depends on the mile: three statute miles of 5,280 feet each. The statute mile itself took its length from a 1593 Act of Parliament, which defined it as 8 furlongs, and its name from the Roman mille passus, a thousand paces of a marching soldier. Since the International Yard and Pound Agreement of 1959, the statute mile has been exactly 1,609.344 meters.
The mile is still in everyday use on roads in the United States and the United Kingdom, while the league dropped out of practical use in the nineteenth century, so modern readers usually need to convert leagues to miles rather than the other way round.
Leagues in History and Literature
Leagues appear most often today in stories. Jules Verne’s Twenty Thousand Leagues Under the Seas (1870) is the best-known example, and its title is often misread as a depth. The deepest point in the ocean, the Challenger Deep, is under 11 km down, while 20,000 leagues is a journey of tens of thousands of miles. Verne meant the distance traveled by Captain Nemo’s submarine, the Nautilus, during the voyage.
| Distance | Leagues (lea) | Miles (mi) |
|---|---|---|
| One league (about an hour's walk) | 1 | 3 |
| Old marine league limit (in land leagues) | 1.150779 | 3.452338 |
| Seven-league boots, one stride | 7 | 21 |
| Twenty Thousand Leagues (English land leagues) | 20,000 | 60,000 |
The seven-league boots of folklore let the wearer cover seven leagues, 21 miles, in a single stride. They appear in Charles Perrault’s 1697 tale Le Petit Poucet (“Hop-o’-My-Thumb”), where the boy steals them from an ogre, and in many later fairy tales. J. R. R. Tolkien also measured journeys in leagues throughout The Lord of the Rings.
Leagues shaped real borders too. The eighteenth-century “cannon-shot rule” set a nation’s territorial waters at one marine league, 3 nautical miles from shore, roughly the range of shore guns. That three-mile limit was widely used until the 1982 UN Convention on the Law of the Sea made 12 nautical miles the standard.
The league’s link to walking time is easy to test. At a steady 3 mph, one league takes an hour, and it is roughly 6,300 steps for an average adult, about the same as the 3 miles to steps conversion. A day’s travel on foot in the pre-modern world was often reckoned at seven to ten leagues, 21 to 30 miles, which is why the magic boots in the stories cover a day’s journey in a single stride.
Leagues also turn up in the names of real places and documents. Spanish and Mexican land grants in Texas and California were described in leagues and varas, and some property lines and county records there still refer to them. Anyone converting those older measurements should use the local Spanish league, not the English one, since the two can differ by a third of a mile or more.
How Many Leagues in a Mile?
One mile is 0.333333 leagues, a third of a league. To convert miles to leagues, divide by 3: a 26.2-mile marathon is 8.73 leagues, and the 60,000 miles of the Nautilus’s voyage come back to exactly 20,000 leagues.