Mile
The mile is an English unit of length of linear measure equal to 5,280 feet, or 1,760 yards, and standardised as exactly 1,609.344 metres by international agreement in 1959.
With qualifiers, "mile" is also used to describe or translate a wide range of units derived from or roughly equivalent to the Roman mile, such as the nautical mile, the Italian mile, and the Chinese mile. The Romans divided their mile into 5,000 Roman feet but the greater importance of furlongs in pre-modern England meant that the statute mile was made equivalent to 8 furlongs or 5,280 feet in 1593. This form of the mile then spread to the British-colonized nations some of which continue to employ the mile. The US Geological Survey now employs the metre for official purposes but legacy data from its 1927 geodetic datum has meant that a separate US survey mile continues to see some use. While most countries replaced the mile with the kilometre when switching to the International System of Units, the international mile continues to be used in some countries, such as Liberia, the United Kingdom, the United States, and a number of countries with fewer than one million inhabitants, most of which are UK or US territories, or have close historical ties with the UK or US.
The mile was usually abbreviated m. in the past in the USA but is now written as mi to avoid confusion with the SI metre. However, derived units, such as miles per hour or miles per gallon, continue to be abbreviated as mph and mpg, respectively. In the United Kingdom, road signs still abbreviate mile to m.
Name
The modern English word mile derives from Middle English myle and Old English mīl, which was cognate with all other Germanic terms for "miles". These derived from the nominal ellipsis form of mīlle passus or mīlia passuum, the Roman mile of one thousand paces.The present international mile is usually what is understood by the unqualified term "mile". When this distance needs to be distinguished from the [|nautical] mile, the international mile may also be described as a "land mile" or "statute mile". In British English, the "statute mile" may refer to the present international miles or to any other form of English mile since the 1593 Act of Parliament, which set it as a distance of 1,760 yards. Under American law, however, the "statute mile" refers to the US survey mile. Foreign and historical units translated into English as miles usually employ a qualifier to describe the kind of mile being used but this may be omitted if it is obvious from the context, such as a discussion of the 2nd-century Antonine Itinerary describing its distances in terms of "miles" rather than "Roman miles".
The mile has been variously abbreviated—with and without a trailing period—as m, M, ml, and mi. The American National Institute of Standards and Technology now uses and recommends mi to avoid confusion with the SI metre and millilitre. However, derived units such as miles per hour or miles per gallon continue to be abbreviated as mph and mpg rather than mi/h and mi/gal. In the United Kingdom road signs use m as the abbreviation for mile though height and width restrictions also use m as the abbreviation for the metre, which may be displayed alongside feet and inches. The BBC style holds that "There is no acceptable abbreviation for 'miles'" and so it should be spelled out when used in describing areas.
Historical miles
Roman mile
The Roman mile consisted of a thousand paces as measured by every other step—as in the total distance of the left foot hitting the ground 1,000 times. The ancient Romans, marching their armies through uncharted territory, would often push a carved stick in the ground after each 1,000 paces. Well-fed and harshly driven Roman legionaries in good weather thus created longer miles. The distance was indirectly standardised by Agrippa's establishment of a standard Roman foot in 29 BC, and the definition of a pace as 5 feet. An Imperial Roman mile thus denoted 5,000 Roman feet. Surveyors and specialised equipment such as the decempeda and dioptra then spread its use.In modern times, Agrippa's Imperial Roman mile was empirically estimated to have been about in length.
In Hellenic areas of the Empire, the Roman mile was used beside the native Greek units as equivalent to 8 stadia of 600 Greek feet. The mílion continued to be used as a Byzantine unit and was also used as the name of the zero mile marker for the Byzantine Empire, the Milion, located at the head of the Mese near Hagia Sophia.
The Roman mile also spread throughout Europe, with its local variations giving rise to the different units below.
Also arising from the Roman mile is the milestone. All roads radiated out from the Roman Forum throughout the Empire – 50,000 miles of stone-paved roads. At every mile was placed a shaped stone. Originally these were stone obelisks made from granite, marble, or whatever local stone was available. On these was carved a Roman numeral, indicating the number of miles from the centre of Rome – the Forum. Hence, one always knew how far one was from Rome.
Italian mile
The Italian mile was traditionally considered a direct continuation of the Roman mile, equal to 1000 paces, although its actual value over time or between regions could vary greatly. It was often used in international contexts from the Middle Ages into the 17th century and is thus also known as the "geographical mile", although the [|geographical mile] is now a separate standard unit.Arabic mile
The Arabic mile was not the common Arabic unit of length; instead, Arabs and Persians traditionally used the longer parasang or "Arabic league". The Arabic mile was, however, used by medieval geographers and scientists and constituted a kind of precursor to the nautical or geographical mile. It extended the Roman mile to fit an astronomical approximation of 1 arcminute of latitude measured directly north-and-south along a meridian. Although the precise value of the approximation remains disputed, it was somewhere between 1.8 and 2.0 km.British and Irish miles
English mile
The "old English mile" of the medieval and early modern periods varied but seems to have measured about 1.3 international miles. The English long continued the Roman computations of the mile as 5000 feet, 1000 paces, or 8 longer divisions, which they equated with their "furrow's length" or furlong.The origins of English units are "extremely vague and uncertain", but seem to have been a combination of the Roman system with native British and Germanic systems both derived from multiples of the barleycorn. Probably by the reign of Edgar in the 10th century, the nominal prototype physical standard of English length was an arm-length iron bar held by the king at Winchester; the foot was then one-third of its length. Henry I was said to have made a new standard in 1101 based on his own arm. Following the issuance of Magna Carta, the barons of Parliament directed John and his son to keep the king's standard measure and weight at the Exchequer, which thereafter verified local standards until its abolition in the 19th century. New brass standards are known to have been constructed under Henry VII and Elizabeth I.
Arnold's Customs of London recorded a mile shorter than previous ones, coming to 0.947 international miles or 1.524 km.
The English statute mile was established by a Weights and Measures Act of Parliament in 1593 during the reign of Queen Elizabeth I. The act on the Composition of Yards and Perches had shortened the length of the foot and its associated measures, causing the two methods of determining the mile to diverge. Owing to the importance of the surveyor's rod in deeds and surveying undertaken under Henry VIII, decreasing the length of the rod by would have amounted to a significant tax increase. Parliament instead opted to maintain the mile of 8 furlongs and to increase the number of feet per mile from the old Roman value. The applicable passage of the statute reads: "A Mile shall contain eight Furlongs, every Furlong forty Poles, and every Pole shall contain sixteen Foot and half." The statute mile therefore contained 5,280 feet or 1,760 yards. The distance was not uniformly adopted. Robert Morden had multiple scales on his 17th-century maps which included continuing local values: his map of Hampshire, for example, bore two different "miles" with a ratio of and his map of Dorset had three scales with a ratio of. In both cases, the traditional local units remained longer than the statute mile.
Welsh mile
The Welsh mile was 3 miles and 1470 yards long. It comprised 9000 paces, each of 3 Welsh feet of 9 inches. Along with other Welsh units, it was said to have been codified under Dyfnwal the Bald and Silent and retained unchanged by Hywel the Good. Along with other Welsh units, it was discontinued following the conquest of Wales by the English under Edward I in the 13th century.Scots mile
The Scots mile was longer than the English mile, as mentioned by Robert Burns in the first verse of his poem "Tam o' Shanter". It comprised 8 furlongs divided into 320 falls or faws. It varied from place to place but the most accepted equivalencies are 1,976 Imperial yards.It was legally abolished three times: first by a 1685 act of the Scottish Parliament, again by the 1707 Treaty of Union with England, and finally by the Weights and Measures Act 1824. It had continued in use as a customary unit through the 18th century but had become obsolete by its final abolition.
Irish mile
The Irish mile measured 2240 yards: approximately 1.27 statute miles or 2.048 kilometres. It was used in Ireland from the 16th century plantations until the 19th century, with residual use into the 20th century. The units were based on "English measure" but used a linear perch measuring as opposed to the English rod of.Other historical miles
- The Dutch mile has had different definitions throughout history. One of the older definitions was 5600 ells. But the length of an ell was not standardised, so that the length of a mile could range between 3280 m and 4280 m. The Dutch mile also has had historical definitions of one hour's walking, which meant around 5 km, or 20,000 Amsterdam or Rhineland feet. Besides the common Dutch mile, there is also the geographical mile. 15 geographical Dutch miles equal one degree of longitude on the equator. Its value changed as the circumference of the earth was estimated to a better precision. But at the time of usage, it was around 7157 m. The metric system was introduced in the Netherlands in 1816, and the metric mile became a synonym for the kilometre, being exactly 1000 m. Since 1870, the term "mile" was replaced by the equivalent "kilometre". Today, the word "mile" is no longer used, apart from some old proverbs.
- The German mile was 24,000 German feet. The standardised Austrian mile used in southern Germany and the Austrian Empire was 7.586 km; the Prussian mile used in northern Germany was 7.5325 km. Following its standardisation by Ole Rømer in the late 17th century, the Danish mile was precisely equal to the Prussian mile and likewise divided into 24,000 feet. These were sometimes treated as equivalent to 7.5 km. Earlier values had varied: the Sjællandske miil, for instance, had been 11.13 km. The Germans also used a longer version of the geographical mile.
- The Saxon Post mile varied from 8.3790 km to 8.9374 km before being standardised as 8.3536 km.
- The Portuguese mile used in Portugal and Brazil was 2.0873 km prior to metrication.
- The Russian mile was 7.468 km, divided into 7 versts.
- The Croatian mile, first devised by the Jesuit Stjepan Glavač on a 1673 map, is the length of an arc of the equator subtended by ° or 11.13 km exactly. The previous Croatian mile, now known as the "ban mile", had been the Austrian mile given above.
- The Ottoman mile was 1,894.35 m, which was equal to 5,000 Ottoman foot. After 1933, the Ottoman mile was replaced with the modern Turkish mile.
International mile
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. However, the current National Topographic Database of the Survey of India is based on the metric WGS-84 datum, which is also used by the Global Positioning System.
The difference from the previous standards was 2 ppm, or about 3.2 millimetres per mile. The U.S. standard was slightly longer and the old Imperial standards had been slightly shorter than the international mile. When the international mile was introduced in English-speaking countries, the basic geodetic datum in America was the North American Datum of 1927. This had been constructed by triangulation based on the definition of the foot in the Mendenhall Order of 1893, with 1 foot = metres and the definition was retained for data derived from NAD27, but renamed the U.S. survey foot to distinguish it from the international foot.
The exact length of the land mile varied slightly among English-speaking countries until the international yard and pound agreement in 1959 established the yard as exactly 0.9144 metres, giving a mile of exactly 1,609.344 metres. The U.S. adopted this international mile for most purposes, but retained the pre-1959 mile for some land-survey data, terming it the U. S. survey mile. In the United States, statute mile normally refers to the survey mile, about 3.219 mm longer than the international mile.
While most countries abandoned the mile when switching to the metric system, the international mile continues to be used in some countries, such as Liberia, Myanmar, the United Kingdom and the United States. It is also used in a number of territories with less than a million inhabitants, most of which are U.K. or U.S. territories, or have close historical ties with the U.K. or U.S.: American Samoa, Bahamas, Belize, British Virgin Islands, Cayman Islands, Dominica, Falkland Islands, Grenada, Guam, The N. Mariana Islands, Samoa, St. Lucia, St. Vincent & The Grenadines, St. Helena, St. Kitts & Nevis, the Turks & Caicos Islands, and the U.S. Virgin Islands.
The mile is even encountered in Canada, though this is predominantly in rail transport and horse racing, as the roadways have been metricated since 1977. The Republic of Ireland replaced miles with kilometres, and speeds in miles per hour with kilometres per hour, gradually. The process was completed in 2005.
U.S. survey mile
The U.S. survey mile is 5,280 survey feet, or about 1,609.347 metres. In the United States, the term statute mile formally refers to the survey mile, but for most purposes, the difference between the survey mile and the international mile is insignificant—one international mile is U.S. survey miles—so statute mile can be used for either. But in some cases, such as in the U.S. State Plane Coordinate Systems, which can stretch over hundreds of miles, the accumulated difference can be significant, so it is important to note that the reference is to the U.S. survey mile.The United States redefined its yard in 1893, and this resulted in U.S. and Imperial measures of distance having very slightly different lengths.
The North American Datum of 1983, which replaced the NAD27, is defined in metres. State Plane Coordinate Systems were then updated, but the National Geodetic Survey left individual states to decide which definition of the foot they would use. All State Plane Coordinate Systems are defined in metres, and 42 of the 50 states only use the metre-based State Plane Coordinate Systems. 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.
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 is hardly significant, given the precision of normal surveying measurements over short distances. 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.
In October 2019, U.S. National Geodetic Survey and National Institute of Standards and Technology announced their joint intent to retire the U.S. survey foot and U.S. survey mile, as permitted by their 1959 decision, with effect from the end of 2022.
Nautical mile
The nautical mile was originally defined as one minute of arc along a meridian of the Earth. 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. The Earth is not perfectly spherical but an oblate spheroid, so the length of a minute of latitude increases by 1% from the equator to the poles. Using the WGS84 ellipsoid, the commonly accepted Earth model for many purposes today, one minute of latitude at the WGS84 equator is 6,046 feet and at the poles is 6,107.5 feet. The average is about 6,076 feet.In the United States, the nautical mile was defined in the 19th century as 6,080.2 feet, whereas in the United Kingdom, the Admiralty nautical mile was defined as 6,080 feet and was about 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.
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 6,000 feet. The radar mile is a unit of time, equal to the time required for a radar pulse to travel a distance of two miles. Thus, the radar statute mile is 10.8 μs and the radar nautical mile is 12.4 μs.
Geographical mile
The geographical mile is based upon the length of a meridian of latitude. The German geographical mile was previously ° of latitude.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, are several examples. Typically the largest streets are about a mile apart, with others at smaller intervals. In the Manhattan borough of New York City "streets" are close to 20 per mile, while the major numbered "avenues" are about six per mile.Metric mile
The informal term "metric mile" is used in some countries, in sports such as track and field athletics and speed skating, to denote a distance of. The 1500 meters is the premier middle distance running event in Olympic sports. In United States high-school competition, the term is sometimes used for a race of.Scandinavian mile
The Scandinavian mile remains in common use in Norway and Sweden, where it has meant precisely 10 km since metrication in 1889. It is used in informal situations and in measurements of fuel consumption, which are often given as litres per mil. In formal situations and where confusion may occur with international miles, it is avoided in favour of kilometres.The Swedish mile was standardised as 36,000 Swedish feet or 10.687 km in 1649; before that it varied by province from about 6 to 14.485 km.
Before metrication, the Norwegian mile was 11.298 km.
The traditional Finnish peninkulma was translated as mil in Swedish and also set equal to 10 km during metrication in 1887, but is much less commonly used.
Comparison table
A comparison of the different lengths for a "mile", in different countries and at different times in history, is given in the table below. Leagues are also included in this list because, in terms of length, they fall in between the short West European miles and the long North, Central and Eastern European miles.| Length | Name | Country used | From | To | Definition | Remarks |
| 960–1,152 | talmudic mil | Palestine | Biblical and Talmudic units of measurement | |||
| 1,480 | mille passus, milliarium | Roman Empire | Ancient Roman units of measurement | |||
| 1,486.6 | miglio | Sicily | ||||
| 1,524 | London mile | England | ||||
| 1,609.3426 | mile | Great Britain | 1592 | 1959 | 1,760 yards | Over the course of time, the length of a yard changed several times and consequently so did the English, and from 1824, the imperial mile. The statute mile was introduced in 1592 during the reign of Queen Elizabeth I |
| 1,609.344 | mile | some Anglosaxon countries | 1959 | today | 1760 yards | In 1 July 1959 the imperial mile was standardized to an exact length in metres |
| 1,609.3472 | mile | United States | 1893 | today | 1,760 yards | From 1959 also called the U.S. Survey Mile. From then its only utility has been land survey, before it was the standard mile. From 1893 its exact length in metres was: × 1760 |
| 1,820 | Italy | |||||
| 1,852 | nautical mile | international | today | approx. 1 minute of arc | Measured at a circumference of 40,000 km. Abbreviation: NM, nm | |
| 1,852.3 | 1 meridian minute | |||||
| 1,853.181 | nautical mile | Turkey | ||||
| 1,855.4 | 1 equatorial minute | Although the NM was defined on the basis of the minute, it varies from the equatorial minute, because at that time the circumference of the equator could only be estimated at 40,000 km. | ||||
| 2,065 | Portugal | |||||
| 2,220 | Gallo-Roman league | Gallo-Roman culture | 1.5 miles | Under the reign of Emperor Septimius Severus, this replaced the Roman mile as the official unit of distance in the Gallic and Germanic provinces, although there were regional and temporal variations. | ||
| 2,470 | Sardinia, Piemont | |||||
| 2,622 | Scotland | |||||
| 2,880 | Ireland | |||||
| 3,780 | Flanders | |||||
| 3,898 | French lieue | France | 2,000 "body lengths" | |||
| 4,000 | general or metric league | |||||
| 4,000 | legue | Guatemala | - | |||
| 4,190 | legue | Mexico | = 2,500 tresas = 5,000 varas | |||
| 4,444.8 | landleuge | ° of a circle of longitude | ||||
| 4,452.2 | lieue commune | France | Units of measurement in France before the French Revolution | |||
| 4,513 | legue | Paraguay | ||||
| 4,513 | legua | Chile, | = 36 cuadros = 5400 varas | |||
| 4,808 | Switzerland | |||||
| 4,828 | English land league | England | 3 miles | |||
| 4,800 4,900 | Germanic rasta, also doppelleuge | |||||
| 5,000 | légua nova | Portugal | ||||
| 5,196 | legua | Bolivia | = 40 ladres | |||
| 5,152 | legua argentina | Argentina, Buenos Aires | = 6,000 varas | |||
| 5,154 | legue | Uruguay | ||||
| 5,200 | Bolivian legua | Bolivia | ||||
| 5,370 | legue | Venezuela | ||||
| 5,500 | Portuguese legua | Portugal | ||||
| 5,510 | legue | Ecuador | ||||
| 5,510 | Ecuadorian legua | Ecuador | ||||
| 5,532.5 | Landleuge | Prussia | ||||
| 5,540 | legue | Honduras | ||||
| 5,556 | Seeleuge | ° of a circle of longitude 3 nautical miles | ||||
| 5,570 | legua | Spain and Chile | Spanish customary units | |||
| 5,572 | legua | Colombia | = 3 Millas | |||
| 5,572.7 | legue | Peru | = 20,000 feet | - | ||
| 5,572.7 | legua antigua old league | Spain | = 3 millas = 15,000 feet | |||
| 5,590 | légua | Brazil | = 5,000 varas = 2,500 bracas | |||
| 5,600 | Brazilian legua | Brazil | ||||
| 5,685 | Fersah | Ottoman Empire | 1933 | 4 Turkish miles | Derived from Persian Parasang. | |
| 5,840 | Dutch mile | Holland | ||||
| 6,170 | milltir | Wales | 13thC | 9000 camau | Eclipsed by the conquest of Wales by Edward I | |
| 6,197 | légua antiga | Portugal | = 3 milhas = 24 estadios | |||
| 6,240 | Persian legue | Persia | ||||
| 6,277 | Luxembourg | |||||
| 6,280 | Belgium | |||||
| 6,687.24 | legua nueva new league, since 1766 | Spain | = 8,000 varas | |||
| 6,797 | Landvermessermeile | Saxony | ||||
| 7,400 | Netherlands | |||||
| 7,409 | 4 meridian minutes | |||||
| 7,419.2 | Kingdom of Hanover | |||||
| 7,419.4 | Duchy of Brunswick | |||||
| 7,420.4 7,414.9 | Bavaria | |||||
| 7,420.439 | geographic mile | equatorial grads | ||||
| 7,421.6 | 4 equatorial minutes | |||||
| 7,448.7 | Württemberg | |||||
| 7,450 | Hohenzollern | |||||
| 7,467.6 | Russia | 7 verst | Obsolete Russian units of measurement | |||
| 7,480 | Bohemia | |||||
| 7,500 | kleine / neue Postmeile | Saxony | 1840 | German Empire, North German Confederation, Grand Duchy of Hesse, Russia | ||
| 7,532.5 | Landmeile | Denmark, Hamburg, Prussia | primarily for Denmark defined by Ole Rømer | |||
| 7,585.9 | Postmeile | Austro-Hungary | Austrian units of measurement | |||
| 7,850 | Milă | Romania | ||||
| 8,800 | Schleswig-Holstein | |||||
| 8,888.89 | Baden | |||||
| 9,062 | mittlere Post- / Polizeimeile | Saxony | 1722 | |||
| 9,206.3 | Electorate of Hesse | |||||
| 9,261.4 | 5 meridian minutes | |||||
| 9,277 | 5 equatorial minutes | |||||
| 9,323 | alte Landmeile | Hanover | 1836 | |||
| 9,347 | alte Landmeile | Hanover | 1836 | |||
| 9,869.6 | Oldenburg | |||||
| 10,000 | metric mile, Scandinavian mile | Norway, Sweden | still commonly used today, e. g. for road distances.; equates to the myriametre | |||
| 10,044 | große Meile | Westphalia | ||||
| 10,670 | Finland | |||||
| 10,688.54 | mil | Sweden | 1889 | In normal speech, "mil" means a Scandinavian mile of 10 km. | ||
| 11,113.7 | 6 meridian minutes | |||||
| 11,132.4 | 6 equatorial minutes | |||||
| 11,299 | mil | Norway | was equivalent to 3000 Rhenish rods. |
Similar units:
- 1066.8 m – verst, see also Obsolete Russian units of measurement
Idioms
- A is used colloquially to denote a very long distance.
- "A miss is as good as a mile"
- "Give him an inch and he'll take a mile" – a corruption of "Give him an inch and he'll take an ell"
- "Missed by a mile"
- "Go a mile a minute"
- "Talk a mile a minute"
- "To go the extra mile"
- "Miles away"
- "Milestone"
Citations