"Miles" redirects here. For other uses see Mile (disambiguation) and Miles (disambiguation). mile statute nautical 1.609344 km 1.852 km 1609.344 m 1852 m 1760 yd 2025.372 yd 5280 ft 6076.115 ft 63360 in 72913.39 in A British road sign on Skye with distances in miles (a Scottish Gaelic bilingual sign)

A mile is a unit of length in a number of different systems. In contemporary English a mile most commonly refers to the statute mile of 5280 feet (1760 yards or 1609.344 metres)citation needed or the U.S. survey mile of 5280 U.S. survey feet (1609.3472 m).1 It is about a third of the old measurement the league. A mile sometimes refers to the nautical mile (1852 metres (6076.12 ft)) used for aerial and navigation purposes.2

The use of the mile as a unit of measurement is now largely confined to the United States and the United Kingdom. There are many other historical miles and similar units in other systems translated as miles in English varying between one and fifteen kilometres.

There have been several abbreviations for mile (with and without trailing period): mi ml m M. In the United States the National Institute of Standards and Technology now uses and recommends mi3 but in everyday usage (at least in the United States and in the United Kingdom) units such as miles per hour and miles per gallon are almost always abbreviated as mph or mpg (rather than mi/h or mi/gal). Contents 1 Origin 2 Statute mile 2.1 Historical miles in Britain and Ireland 2.1.1 Scots mile 2.1.2 Irish mile 2.2 Metric mile 3 Nautical mile 3.1 Related nautical units 4 Roman mile 5 Other miles 6 Grid system 7 Idioms 8 See also 9 Notes 10 References 11 External links Origin

The word mile originally derives from the Old English word ml which in turn was ultimately derived from the Latin word millia meaning "thousand".4 The English mile is derived from the Latin mille passuum (one thousand paces) but in other coutries the word "mile" (meile in German mijl in Dutch) was derived from the Latin miliarium spatium (one thousand "intervals").5 Statute mile

The statute mile was defined by an English Act of Parliament (hence the name) in 1592 during the reign of Queen Elizabeth I as being 1760 yards (5280 feet about 1609 metres).6 For surveying the statute mile is divided into eight furlongs; each furlong is ten chains; each chain is four rods (also known as poles or perches); and each rod is 25 links. This makes the rod equal to 5 yards or 16 feet in both Imperial and U.S. usage.

The exact conversion of the mile to SI units depends on which definition of the yard is used. Different English-speaking countries maintained independent physical standards for the yard that were found to differ by small but measurable amounts and even to slowly shorten in length.7 The United States redefined the U.S. yard in 1893 but this resulted in U.S. and Imperial measures of distance having very slightly different values. The difference was resolved in 1959 with the definition of the international yard in terms of the metre by Australia Canada New Zealand South Africa the United Kingdom and the United States.8 The "international mile" of 1760 international yards is exactly 1609.344 metres.

The difference from the previous standards was 2 ppm or about 3.2 millimetres (1/8 inch) in each mile the old U.S. standard being slightly longer and the old Imperial standards slightly shorter than the international mile. The older standards for the yard (and hence the foot and the mile) continue in use for some surveying purposes in the United States9 and the old Imperial value of the yard was used in converting measurements to metric values in India in a 1976 Act of the Indian Parliament.10 However The current National Topographic Database of the Survey of India is based on the metric WGS-84 datum11 which is also used by the Global Positioning System.

For most applications the difference between the two definitions is insignificant one international foot is exactly 0.999998 of a U.S. survey foot. However a difference of about 3.2 millimetres (1/8 inch) per mile affects the definition of the State Plane Coordinate Systems (SPCSs) which can stretch over hundreds of miles.12 When international measure was introduced in the English-speaking countries the basic geodetic datum in North America was the North American Datum of 1927 (NAD27) which had been constructed by triangulation based on the definition of the foot in the Mendenhall Order of 1893 that is 1 foot  12003937 metres. This definition was retained for data derived from NAD27 but renamed the U.S. survey foot to distinguish it from the international foot.9

The North American Datum of 1983 (NAD83) which is defined in metres replaced The NAD27 in the 1980s. The State Plane Coordinate Systems were also updated but the National Geodetic Survey left the individual states to decide which (if any) definition of the foot they would use. All State Plane Coordinate Systems are defined in meters and 42 of the 50 states use the meter-based State Plane Coordinate Systems only. However eight states also have State Plane Coordinate Systems defined in feet seven of them in U.S. Survey feet and one in international feet.12 State legislation in the U.S. is important for determining which conversion factor from the metric datum is to be used for land surveying and real estate transactions even though the difference (2 ppm) is hardly significant given the precision of normal surveying measurements over short distances (usually much less than a mile). Twenty-four states have legislated that surveying measures be based on the U.S. survey foot eight have legislated that they be based on the international foot and eighteen have not specified which conversion factor to use.12 Historical miles in Britain and Ireland The statute of Elizabeth I was not the only definition of the mile in Britain and Ireland. Perhaps the earliest tables of English linear measures Arnold's Customs of London (c. 1500) indicates a mile consisted of 8 furlongs each of 625 feet for a total of 5000 feet (1666 yards 0.947 statute miles 1524 metres):6 this is the same definition of the mile in terms of feet as used by the Romans. The "old English" mile of medieval and early modern times appears to have measured approximately 1.3 statute miles (1.9 km).13 Scots mile Main article: Scots mile The Scots mile was longer than the English mile but varied in length from place to place.14 It was formally abolished by an Act of the Parliament of Scotland in 168515 and again by the Treaty of Union with England in 170716 but continued in use as a customary unit during the 18th century. It was obsolete by the time of its final abolition by the Weights and Measures Act 1824.14 An estimate of its length can be made from other Scots units: in Scots the rod was usually called the fall or faw and was equal to six ells of 37 inches.17 As there are 320 rods in a mile this would make the Scots mile equal to 5920 feet (1973 yards 1.12 statute miles 1804 metres). Other estimates are similar.64 Irish mile The Irish mile was longer still.13 In Elizabethan times four Irish miles was often equated to five English though whether the statute mile or the "old English" mile is unclear.13 By the seventeenth century it was 2240 yards (6720 feet 1.27 statute miles 2048 metres).41819 Again the difference arose from a different length of the rod in Ireland (usually called the perch locally): 21 feet as opposed to 16 feet in England.1820 From 1774 through the 1801 union with Britain until the 1820s the grand juries of 25 Irish counties commissioned surveyed maps at scales of one or two inches per Irish mile.2122 Scottish engineer William Bald's County Mayo maps of 180930 were drawn in English miles and rescaled to Irish miles for printing.23 The HowthDublin Post Office extension of the LondonHolyhead turnpike engineered by Thomas Telford had mileposts in English miles.24 Although legally abolished by the Weights and Measures Act 1824 the Irish mile was used till 1856 by the Irish Post Office.25 The Ordnance Survey of Ireland from its establishment in 1824 used English miles.26 In 1894 Alfred Austin complained after visiting Ireland that "the Irish mile is a fine source of confusion when distances are computed. In one county a mile means a statute mile in another it means an Irish mile".27 When the Oxford English Dictionary definition of "mile" was published in 190628 it described the Irish mile as "still in rustic use".4 A 1902 guide says regarding milestones "Counties Dublin Waterford Cork Antrim Down and Armagh use English but Donegal Irish Miles; the other counties either have both or only one or two roads have Irish".29 Variation in signage persisted till the publication of standardised road traffic regulations by the Irish Free State in 1926.30 In 1937 a man prosecuted for driving outside the 15-mile limit of his licence offered the unsuccessful defence that since the state was independent the limit ought to use Irish miles "just as no one would ever think of selling land other than as Irish acres".31 A 1965 proposal by two TDs to replace statute miles with Irish miles in a clause of the Road Transport Act was rejected.32 The term is now obsolete as a specific measure33 though an "Irish mile" colloquially is a long but vague distance akin to a "country mile".34 Metric mile The term metric mile is used in sports such as track and field athletics and speed skating to denote a distance of 1500 metres (about 4921 ft). In United States high school competition the term is sometimes used for a race of 1600 metres (about 5249 ft).35 Nautical mile On the utility of the nautical mile Each circle shown is a great circle the analog of a line in spherical trigonometry and hence the shortest path connecting two points on the globular surface. Meridians are great circles that pass through the poles. Main article: Nautical mile The nautical mile was originally defined as one minute of arc along a meridian arc of the Earth.36 It is a convenient reference since it is fairly constant at all latitudes in contrast with degrees of longitude which vary from 60 NM at the equator to zero at the poles. Navigators use dividers to step off the distance between two points on the navigational chart then place the open dividers against the minutes-of-latitude scale at the edge of the chart and read off the distance in nautical miles.37 Since it is now known that the Earth is not perfectly spherical but an oblate spheroid the length derived from this method varies slightly from the equator to the poles. For instance using the WGS84 Ellipsoid the commonly accepted Earth model for many purposes today one minute of latitude at the WGS84 equator is 6087 feet and at the poles is 6067 feet. On average it is about 6076 feet (about 1852 metres or 1.15 statute miles). In the United States the nautical mile was defined in the nineteenth century as 6080.2 feet (1853.249 m) whereas in the United Kingdom the Admiralty nautical mile was defined as 6080 feet (1853.184 m) and was approximately one minute of latitude in the latitudes of the south of the UK. Other nations had different definitions of the nautical mile but it is now internationally defined to be exactly 1852 metres. Related nautical units The nautical mile per hour is known as the knot. Nautical miles and knots are almost universally used for aeronautical and maritime navigation because of their relationship with degrees and minutes of latitude and the convenience of using the latitude scale on a map for distance measuring. The data mile is used in radar-related subjects and is equal to 6000 feet (1.8288 kilometres).38 The radar mile is a unit of time (in the same way that the light year is a unit of distance) equal to the time required for a radar pulse to travel a distance of two miles (one mile each way). Thus the radar statute mile is 10.8 s and the radar nautical mile is 12.4 s.39 Roman mile Various historic miles/leagues from a German textbook dated 1848 The Romans were first to use a unit of long distance mille passuum (literally "a thousand paces" in Latin each pace being two steps). It denoted a distance of 1000 paces or 5000 Roman feet and is estimated to be about 1479 metres (1617 yards). This unit is now known as the Roman mile.40 The Roman mile spread throughout the Roman Empire often with modifications to fit local systems of measurements. Other miles The Arab mile (or Arabic mile) was a unit of length used by medieval Muslim geographers. Its precise length is uncertain but is believed to be around 1925 metres.citation needed The Danish mil (traditional) was 24000 Danish feet or 7532.5 metres. Sometimes it was interpreted as exactly 7.5 kilometres. It is the same as the north German Meile (below).41 The Meile was a traditional unit in German-speaking countries much longer than a western European mile. It was 24000 German feet; the SI equivalent was 7586 metres in Austria or 7532.5 metres in northern Germany. There was a version known as the geographische Meile which was 4 Admiralty nautical miles 7412.7 metres or 1/15 degree.42 In Norway and Sweden a mil is a unit of length equal to 10 kilometres and commonly used in everyday language. However in more formal situations such as on road signs and when there is risk of confusion with English miles kilometres are used instead. The traditional Swedish mil spanned the range from 6000-14485 metres depending on province. It was however standardized in 1649 to 36000 Swedish feet or 10.687 km.41 The Norwegian mil was 11.298 kilometres. When the metric system was introduced in the Norwegian-Swedish union in 1889 it standardized the mil to exactly 10 kilometres.41 The Portuguese milha was a unit of length used in Portugal and Brazil before the adoption of the metric system. It was equal to 2087.3 metres.43 The Russian milya ( ) was a traditional Russian unit of distance equal to 7 verst or 7.468 km. The hrvatska milja (Croatian mile) is 11130 metres 11.13 km 1/10 of equator's degree44 first time used by Jesuit Stjepan Glava on a map from 1673. The banska milja (also called hrvatska milja) (mile of Croatian Ban Croatian mile) was 7586 meters  7.586 kilometres or 24000 feet (the same as the Austrian mile).45 Grid system Cities in the continental United States often have streets laid out by miles. Detroit Indianapolis Chicago Phoenix Philadelphia Las Vegas Los Angeles and Miami and Stone Harbor New Jersey are several examples. Typically the largest streets are about a mile apart with others at half-mile and quarter-mile intervals.citation needed Also in the Manhattan borough of New York City "streets" are almost exactly 20 per mile while the major numbered "avenues" are about six per mile.citation needed Idioms Even in English-speaking countries that have moved from the Imperial to the metric system (for example Australia and New Zealand) the mile is still used in a variety of idioms. These include: A country mile is used colloquially to denote a very long distance. "A miss is as good as a mile" (failure by a narrow margin is no better than any other failure) "Give him an inch and he'll take a mile" - a corruption of "Give him an inch and he'll take an ell" 46 (the person in question will become greedy if shown generosity) "Missed by a mile" (missed by a wide margin) "Talk a mile a minute" (speak at a rapid rate) "To go the extra mile" (to put in extra effort) "Miles away" (lost in thought or daydreaming) "Milestone" (an event indicating significant progress) See also Anthropic units Fibonacci sequence for miles converting to kilometers Four-minute mile Geographical mile Mile run Section lines Square mile United States customary units Data mile Metric mile Food miles Notes http://physics.nist.gov/Pubs/SP447/app9.pdf International Bureau of Weights and Measures (2006) The International System of Units (SI) (8th ed.) p. 127 ISBN 92-822-2213-6 http://www.bipm.org/utils/common/pdf/sibrochure8en.pdf  Tina Butcher et al. ed. (2007) Appendix C p. C-13. a b c d T.F. Hoad ed (1996). The Concise Oxford Dictionary of English Etymology. Oxford: Oxford University Press. ISBN 0-19-2830988.  Karl Ernst Georges ed (1910) (in German). Kleines deutsch-lateinisches Handwrterbuch Small German-Latin Pocket Dictionary. Hannover and Leipzig: Hahnsche Buchhandlung 1910.. p. 1660. http://www.zeno.org/Georges-1910/K/Georges-1910-01-1660. Retrieved 2011-05-26.  a b c Klein (1974 corrected 1988) p. 69. Bigg P. H.; Anderton Pamela (1964). "The United Kingdom standards of the yard in terms of the metre". Br. J. Appl. Phys. 15: 291300. doi:10.1088/0508-3443/15/3/308. http://www.iop.org/EJ/abstract/0508-3443/15/3/308/. . Barbrow & Judson (1976) pp. 16 17 20. a b Astin A. V. Karo H. A.; Mueller F. H. (June 25 1959). "Refinement of Values for the Yard and the Pound." Federal Register Doc. 59-5442. When reading the document it helps to bear in mind that 999998 3937 254. Schedule to the Standards of Weights and Measures Act 1976. Survey of India "National Map Policy 2005". a b c U.S. National Geodetic Survey (undated). "Frequently Asked Questions about the National Geodetic Survey". http://www.ngs.noaa.gov/faq.shtml#Feet. Retrieved May 16 2009. . a b c Andrews J.H. (September 15 2003). "Sir Richard Bingham and the mapping of western Ireland". Proceedings of the Royal Irish Academy (Dublin: Royal Irish Academy) 103C (3): 70 fn.35. http://www.google.ie/urlsat&sourceweb&ctres&cd3&urlhttp%3A%2F%2Fwww.ria.ie%2Fpublications%2Fjournals%2FProcCI%2F2003%2FPC03%2FPDF%2F103C03.pdf&eihA4bSr7PDYysjAf-5-jwDA&usgAFQjCNHsV8Jj9rs9YyTrwYL2NOjPpVDM2w&sig2BtFHv8oe4fkQqKLfylalyA.  a b "mile". Dictionary of the Scottish Language Scottish National Dictionary. http://www.dsl.ac.uk/getent4.phpplen1982&startset25361793&queryMILE&fhitmile&dregionform&dtextsnd#fhit.  "Act for a standard of miles" (June 16 1685). APS viii: 494 c.59. RPS 1685/4/83. Union with England Act 1707 (c. 7) art. 17. "fall faw". Dictionary of the Scottish Language Dictionary of the Older Scottish Tongue. http://www.dsl.ac.uk/getent4.phpqueryfall&sset1&fset20&printset20&searchtypefull&dregionform&dtextall.  a b Petty William (1769) 1691. "XIII: Several miscellany remarks and intimations concerning Ireland and the several matters aforementioned". Tracts chiefly relating to Ireland. The political anatomy of Ireland (2nd ed.). Dublin: Boulter Grierson. p. 375. http://books.google.com/idtPovAAAAMAAJ&printsectitlepage#PRA2-PA375M1. "Eleven Irish miles makes 14 English according to the proportion of the Irish perch of 21 feet to the English of 16 and a half."  Ordnance Survey Ireland. "Frequently Asked Questions". http://www.osi.ie/en/faq/faq3.aspx#faq7. Retrieved February 17 2009.  Rowlett Russ (2001). "Irish mile". How Many A Dictionary of Units of Measurement. University of North Carolina at Chapel Hill. http://www.unc.edu/rowlett/units/dictI.html.  Andrews John Harwood (1975). A paper landscape: the ordnance survey in nineteenth-century Ireland. Clarendon Press. p. 4. ISBN 0198232098.  Andrews John; Paul Ferguson (1995). "22: Maps of Ireland". In Helen Wallis Anita McConnell. Historian's Guide to Early British Maps: A Guide to the Location of Pre-1900 Maps of the British Isles Preserved in the United Kingdom and Ireland. Cambridge University Press. pp. 724. ISBN 0521551528. http://books.google.com/idRanXw3Sv1aUC&pgPR6#PPA72M1.  Storrie Margaret C. (September 1969). "William Bald F. R. S. E. c. 1789-1857; Surveyor Cartographer and Civil Engineer". Transactions of the Institute of British Geographers (Blackwell Publishing on behalf of The Royal Geographical Society) (47): 205231. http://www.jstor.org/stable/621743.  Montgomery Bob (November 17 2004). "Past Imperfect; Milestones: Silent witness to our transport history". The Irish Times: p. 34. http://www.irishtimes.com/newspaper/archive/2004/1117/Pg034.html#Ar03401. Retrieved May 25 2009.  Austin Bourke P. M. (March 1965). "Notes on Some Agricultural Units of Measurement in Use in Pre-Famine Ireland". Irish Historical Studies (Irish Historical Studies Publications Ltd) 14 (55): 236. http://www.jstor.org/stable/30005524.  Smith Angle (1998). "Landscapes of power in nineteenth century Ireland: Archaeology and Ordnance Survey maps". Archaeological Dialogues (Cambridge University Press) 5 (5): 6984. doi:10.1017/S1380203800001173.  Austin Alfred (1900). Spring and Autumn in Ireland. Edinburgh and London: William Blackwood and Sons. p. 4. http://www.archive.org/details/springautumninir00austuoft. Retrieved May 25 2009.  McMorris Jenny; main author Lynda Mugglestone (2000). "Appendix I: OED Sections and Parts". Lexicography and the OED: pioneers in the untrodden forest. Oxford University Press. p. 230. ISBN 0198237847. http://books.google.com/iddkiQbqZLAswC&pgPA230&vqMesne. "MesneMisbirth December 1906"  Inglis Harry R. G. (1902). 'Royal' Road Book of Ireland. Edinburgh: Gall and Inglis. p. 14. http://www.archive.org/details/royalroadbookofi00inglrich.  "Safer roads". The Irish Times: p. 6. October 22 1926. http://www.irishtimes.com/newspaper/archive/1926/1022/Pg006.html#Ar00602. Retrieved May 25 2009.  "Irish miles or English Novel defence made at Bray.". The Irish Times: p. 5. 27 November 1937. http://www.irishtimes.com/newspaper/archive/1937/1127/Pg005.html#Ar00504. Retrieved May 25 2009.  "Carriage of Merchandise by Road". Questions. Oral Answers.. Dil ireann debates. 214. Oireachtas. February 23 1965. p. col.836. http://www.oireachtas-debates.gov.ie/D/0214/D.0214.196502230011.html. Retrieved May 26 2009.  "mile n.1 (draft revision)". Oxford English Dictionary (online edition). Oxford University Press. March 2009. http://dictionary.oed.com/cgi/entry/00309498querytypeword&querywordmile&first1&maxtoshow10&sorttypealpha&searchid2zmg-lV4bBW-5449&resultplace2. Retrieved May 26 2009.  Green Jonathon (2005). Cassell's dictionary of slang (2nd ed.). Weidenfeld & Nicolson. p. 774. ISBN 0304366366.  Rowlett (2005). s.v. mile. Maloney (1978) 34. Maloney (1978) 3435. Rowlett (2005). s.v. data mile. Rowlett (2005). s.v. radar mile. Smith (1875) p. 171. a b c Rowlett (2005). s.v. mil 4. Rowlett (2005) s.v meile. Rowlett (2005). s.v. milha. (Croatian) Centuries of Natural Science in Croatia : Theory and Application Kartografija i putopisi (Croatian) Vijenac Mrvice s banskoga stola Oxford Concise Dictionary - 5th Edition - Oxford Universiry Press - 1964 References American Heritage Dictionary of the English Language (3rd ed.) (1992). Boston: Houghton Mifflin Company. Astin. V. and H. Arnold Karo. (1959). Refinement of values for the yard and the pound Washington DC: National Bureau of Standards republished on National Geodetic Survey web site and the Federal Register (Doc. 59-5442 Filed June 30 1959 8:45 a.m.) Barbrow Louis E. and Lewis V. Judson (1976). Weights and Measures Standards of the United States: a brief history. National Institute of Standards and Technology. Butcher Tina et al. ed. (2007). NIST Handbook 44: Specifications Tolerances and Other Technical Requirements for Weighing and Measuring Devices. Appendix C p. C-13. Klein Herbert Arthur (1974 corrected 1988). The Science of Measurement: A Historical Survey. New York: Dover. (previously published by Simon & Schuster under the title The World of Measurements: Masterpieces Mysteries and Muddles of Metrology) Maloney Elbert S. (1978). Dutton's Navigation and Piloting. 13th Ed. Annapolis: Naval Institute Press. Rowlett Russ (2005). How Many A Dictionary of Units of Measurement. Faculty member's web page at University of North Carolina at Chapel Hill. Accessed 2007-11-10. Smith William (1875). Dictionary of Greek and Roman Antiquities. London: John Murray. pp. 762.  Thompson Ambler and Taylor Barry. (2008). Guide for the Use of the International System of Units (SI) (Special Publication 811). Gaithersburg MD: National Institute of Standards and Technology. External links NIST General Tables of Units of Measurement