Nautical League (nlea)

NauticalHistorical unit (no longer in standard use)

Three nautical miles (5.556 km). Used at sea; the title of Jules Verne's novel counts distance in these.

1 nautical league = 5,556 meters (exactly).

About the nautical league

Jules Verne's 1870 novel title promises twenty thousand leagues beneath the sea, a number that would circle the planet several times over, and the unit behind it is worth unpacking. Leagues descend from a Celtic measure that Rome took over as the leuga, supposedly about what a person could walk in an hour. Seafaring nations later adapted the word to the water, where distance was reckoned from the sea rather than from the road.

At sea, English usage made a league three nautical miles. With the international nautical mile fixed at exactly 1,852 m by a hydrographic conference at Monaco in 1929, that gives 5,556 m, the figure used here, or 5.556 km. It equals thirty cables and covers three minutes of latitude. Earlier national nautical miles differed a little, and Portugal and Spain defined maritime leagues from fractions of a degree of meridian, so values near 5.5 to 6.2 km turn up in older texts. Verne's league was a French unit, a metric one of 4,000 m having been legal in France from 1812 to 1840, and the nautical league is now only historical.

Sources: Wikipedia: League (unit); Wikipedia: Nautical mile

Nautical League conversion chart

1 nautical league expressed in every other length unit:

More Nautical units

• nautical mile (length)
• fathom (length)
• cable length (length)
• ship's watch (time)
• knot (speed)
• compass point (angle)

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