Throughout history many units of length named 'mile' have been used, with widely differing definitions, originating with the Roman mile of approximately 1479 m. The only three still commonly used today are the British (also called statute) mile of precisely 1609.344 m (used in the US and the UK; defined to be 5280 international feet), the international nautical mile of exactly 1852 m, and the U.S. survey mile of approximately 1609.347 m (5280 U.S. survey feet).
The British mile was defined to be equal to 8 furlongs.
The international nautical mile is universally used for aviation, naval and maritime purposes. The statute mile is used by the U.S. and U.K. for measuring distances, especially for road transportation; most countries have switched to using kilometres for these purposes. The U.S. survey mile is used by the U.S. Coast and Geodetic Survey.
--- Rome used 1000 'double steps' for one mile. A double step is two strides by a Roman soldier.