What is a UK nautical league?
A UK nautical league is three UK nautical miles, ie 18,240 feet or 5,559.552 meters, which rounds to 5.56 kilometers. The international nautical league is slightly shorter at 5,556 meters.
Don't confuse it with the land league, which is three statute miles. The nautical league is three nautical miles, about 3.45 statute miles, so it's roughly 15% longer.
Britain's territorial waters once reached one marine league – three nautical miles – from the coast. The limit has been 12 nautical miles, or four leagues, since 1987.
What is a mile?
A mile is an imperial and US unit of length, exactly 1,609.344 meters. The word comes from the Latin mille passus, 'a thousand paces', where a pace was two steps of a marching legionary.
A mile is equivalent to 1760yds or 5280ft.
Road distances in the US and UK are signed in miles, while nearly every other country uses kilometers. Aviation and shipping use the nautical mile instead, which is a different length (1,852 meters).