Miles

Statute miles are (in this day and age) so called to distinguish them from earlier definitions of the mile, and of course from the nautical mile. A statute mile could also be called an "international mile", at least with reference to measurements made after 1963.

In the U. S. the survey mile, which is slightly different, is still an important, if little-known, unit. (Per Rowlett, the old -- 1866 -- definition of the foot divided the standard meter into 39.37 inches. The 1959 (U. S.)/1963 (UK) law defined the foot as exactly .3048 m. Thus, a survey mile is approximately 3.2 mm longer than a statute mile.)

The nautical mile, for what it's worth, was originally defined as approximately 1853.188 m (the Admiralty mile) or 1853.249 m (the U. S. nautical mile), but the international nautical mile, used today, is exactly 1852 m.

from alt.usage.english