View source for Rod (unit)

{{short description|Unit of length}}
{{distinguish|text = a [[Pole (surveying)|surveyor's pole]], upon which a survey instrument is mounted; a [[ranging rod]] used for sighting; or, a [[level staff]], which may also be called a leveling rod}}
{{Use dmy dates|date=January 2023}}
{{Use American English|date=March 2021}}

{{Infobox unit
| name     = rod
| standard = [[imperial units|imperial]]/[[US customary units|US]]&nbsp;units
| quantity = [[length]]
| units1   = Imperial/US&nbsp;units
| inunits1 = {{frac|16|1|2}}&nbsp;[[Foot (unit)|ft]]
| units2   = [[metric system|metric]] ([[SI]]) units
| inunits2 = 5.0292 m
}}

The '''rod''', '''perch''', or '''pole''' (sometimes also '''lug''') is a [[surveying|surveyor's]] tool<ref name="Connections"/> and [[unit of length]] of various historical definitions. In [[Imperial units|British imperial]] and [[United States customary units|US customary units]], it is defined as {{frac|16|1|2}} [[Foot (unit)|feet]], equal to exactly {{frac|1|320}} of a [[mile]], or {{frac|5|1|2}} [[yard]]s (a quarter of a [[surveyor's chain]]), and is exactly 5.0292 meters. The rod is useful as a unit of length because integer multiples of it can form one [[acre]] of square measure (area). The 'perfect acre'<ref name="Connections0"/> is a rectangular area of 43,560 square feet, bounded by sides 660 feet (a [[furlong]]) long and 66 feet (a [[Chain (unit)|chain]]) wide (220 yards by 22 yards) or, equivalently, 40 rods by 4 rods. An acre is therefore 160 square rods or 10 square chains.

The name ''perch'' derives from the [[Ancient Roman units of measurement|Ancient Roman unit]], the ''[[pertica (unit)|pertica]]''.
The measure also has a relationship with the military [[pike (weapon)|pike]] of about the same size. Both measures<ref name="Connections"/> date from the sixteenth century,<ref name="Connections2"/> when the pike was still utilized in national armies. The tool has been supplanted, first by [[Tape measure|steel tapes]] and later by electronic tools such as surveyor lasers and optical target devices for surveying lands. In dialectal English, the term ''lug'' has also been used, although the ''[[Oxford English Dictionary]]'' states that this unit, while usually of {{frac|16|1|2}} feet, may also be of 15, 18, 20, or 21 feet.<ref name=bonten/><ref name="dict-lug"/><ref name=OED-lug>{{Cite OED|lug, n.1}}</ref>

In the United States until 1 January 2023, the rod was often defined as 16.5 US survey feet, or approximately 5.029 210 058 m.<ref>{{Cite web| title = U.S. Survey Foot: Revised Unit Conversion Factors | website = National Institute of Standards and Technology| date = 23 September 2019| accessdate = 3 January 2023| url = https://www.nist.gov/pml/us-surveyfoot/revised-unit-conversion-factors}}</ref>

==History==
[[File:A Meat Stall with the Holy Family Giving Alms - Placard.jpg|thumb|300px|right|The sign <!-- in the upper right corner --> included in [[Pieter Aertsen]]'s painting ''[[A Meat Stall with the Holy Family Giving Alms]]'' reads in [[Flemish dialects|Flemish]]: "behind here are 154 rods of land for sale immediately, either by the rod according to your convenience or all at once".]]
In England, the perch was officially discouraged in favour of the rod as early as the 15th century;<ref>[[Encyclopædia Britannica]], English measure</ref>{{Better source needed|reason=More detail needed - There are many editions of Encyclopædia Britannica and each edition has multiple articles.|date=July 2013}} however, local customs maintained its use. In the 13th century, perches were variously recorded in lengths of {{convert|18|ft|m|2}}, {{convert|20|ft|m|1}}, {{convert|22|ft|m|2}} and {{convert|24|ft|m|2}}; and even as late as 1820, a [[House of Commons of the United Kingdom|House of Commons]] report notes lengths of {{convert|16+1/2|ft|m|2}}, {{convert|18|ft|m|2}}, {{convert|21|ft|m|1}}, {{convert|24|ft|m|2}}, and even {{convert|25|ft|m|2}}.<ref>{{cite book |title=House of Commons Report (Second) of Commissioners to Consider the Subject of Weights and Measures |date=13 July 1820 |series=Parliamentary Papers |volume=HC314 |pages=473–512}}</ref> In [[Ireland]], a perch was standardized at {{convert|21|ft|m|1}}, making an Irish chain, [[furlong]] and mile proportionately longer by 27.27% than the "standard" English measure.<ref>{{cite web |url=http://www.unc.edu/~rowlett/units/dictP.html |title=Units: P |website=unc.edu}}</ref>

Until English King [[Henry VIII of England|Henry VIII]] seized the lands of the [[Roman Catholic Church]] in 1536,<ref name="Connections">{{cite book |last=Burke |first=James |title=Connections: Alternative History of Technology |url=https://books.google.com/books?id=8IjaYgEACAAJ |year=1978 |publisher=Macmillan |isbn=978-0-333-29066-8 |chapter=Chapter 9 |page=304}}</ref> land measures as we now know them were essentially unknown.<ref name="Connections"/> Instead a narrative system of landmarks and lists was used. Henry wanted to raise even more funds for his wars than he'd seized directly from church property (he'd also assumed the debts of the monasteries<ref name="Connections"/>), and as [[James Burke (science historian)|James Burke]] writes and quotes in the book ''[[Connections (book)|Connections]]'' that the English monk [[Richard Benese]] "produced a book on how to survey land using the simple tools of the time, a rod with cord carrying knots at certain intervals, waxed and resined against wet weather." Benese poetically described the measure of an acre in terms of a perch:<ref name="Connections2">''Connections'', pbk. p.263</ref>
{{Cquote|an acre bothe of woodlande, also of fyldlande [heath] is always forty perches in length, and four perches in breadth, though an acre of woodlande be more in quantitie [value, i.e. was more valued commercially] than an acre of fyldelande|Richard Benese per James Burke in ''Connections'', p.263}}
The practice of using surveyor's chains, and perch-length rods made into a detachable stiff chain, came about a century later when iron was a more plentiful and common material. A [[chain (unit)|chain]] is a larger [[Units of measurement|unit]] of [[length]] measuring {{convert|66|ft|4|lk=on}}, or 22 [[yard (unit of length)|yards]], or 100 [[Link (unit)|links]],<ref>{{cite book |title=The Cassell English Dictionary |location=London |date=1990 |page=214 |isbn=0-304-34003-0|last1=Kirkpatrick |first1=Elizabeth Mclaren }}</ref> or 4 rods (20.1168 [[meter]]s). There are 10 chains or 40 rods in a furlong (eighth-mile), and so 80 chains or 320 rods in one [[statute mile]] (1760 yards, 1609.344 m, 1.609344 [[kilometer|km]]); the definition of which was [[Act against Converting of Great Houses into Several Tenements and for Restraint of Inmates and Inclosures in and near about the City of London and Westminster|legally set in 1593]] and popularized by Royal surveyor (called the 'sworn viewer'<ref name="Connections3">"Connections", pbk. p.265</ref>) [[John Ogilby]] only after the [[Great Fire of London]] (1666).

An [[acre]] is defined as the area of 10 square chains (that is, an area of one chain by one furlong), and derives from the shapes of new-tech plows<ref name="Connections0">Connections, pbk. p.63</ref> and the desire to quickly survey seized church lands into a quantity of squares for quick sales<ref name="Connections2"/> by Henry VIII's agents; buyers simply wanted to know what they were buying whereas Henry was raising cash for wars against Scotland and France.<ref name="Connections2"/> Consequently, the surveyor's chain and surveyor rods or poles (the perch) have been used for several centuries in Britain and in many other countries influenced by British practices such as North America and Australia. By the time of the industrial revolution and the quickening of land sales, canal and railway surveys, et al. Surveyor rods such as used by [[George Washington]] were generally made of dimensionally stable metal&mdash;semi-flexible drawn wrought iron linkable bar stock (not steel), such that the four folded elements of a chain were easily transportable through brush and branches when carried by a single man of a surveyor's crew. With a direct ratio to the length of a surveyor's chain and the sides of both an acre and a square (mile), they were common tools used by surveyors, if only to lay out a known plottable baseline in rough terrain thereafter serving as the reference line for instrumental ([[theodolite]]) [[triangulation]]s.

The rod as a [[Surveying|survey]] measure was standardized by [[Edmund Gunter]] in England in 1607 as a quarter of a chain (of {{convert|66|ft|m|2}}), or {{convert|16+1/2|ft|m|2}} long.

===In ancient cultures===
The '''perch''' ([[Pertica (unit)|pertica]]) as a [[Ancient Roman units of measurement|lineal measure in Rome]] (also ''decempeda'') was 10 Roman feet (2.96 metres), and in [[France]] varied from 10 feet (''perche romanie'') to 22 feet (''perche d'arpent''—apparently {{frac|1|10}} of "the range of an arrow"—about {{cvt|220|ft}}). To confuse matters further, by ancient Roman definition, an arpent equalled 120 Roman feet. The related unit of square measure was the ''scrupulum'' or ''decempeda quadrata'', equivalent to about {{convert|8.76|m2|sqft|abbr=on}}.<ref name=smith/>

===In continental Europe===
[[Image:Münster, Historisches Rathaus, Preussische halbe Ruthe -- 2017 -- 9783 (crop).jpg|thumb|300px|right|A standard at the City Hall in [[Münster]], [[Germany]] from 1816; the bar shown is one "Prussian Half Rod" (1.883&nbsp;m) long.]]
Units comparable to the perch, pole or rod were used in many European countries, with names that include {{langx|fr|perche}} and ''canne'', {{langx|de|Ruthe}}, {{langx|it|canna}} and ''pertica'', {{langx|pl|pręt}} and {{langx|es|canna}}. They were subdivided in many different ways, and were of many different lengths.

{| class="wikitable sortable"
|+Rods and similar units in continental Europe{{dubious|date=April 2012}}
|-
! width=240 |Place
! width=130 |Local name
! width=130 |Local equivalent
! width=120 |Metric equivalent (meters)
|-
| [[Aachen]]
| Feldmeßruthe
| align="right" | 16 Fuß
| 	align="center"|4.512<ref name=kruger/>
|-
| [[Amsterdam]]
| Roede
| align="right" | 13 Voet
| align="center"|3.681<ref name="DeGelder1824">{{cite book |url=https://books.google.com/books?id=XYVbAAAAQAAJ |title=Allereerste Gronden der Cijferkunst |trans-title=Introduction to Arithmetic |first=Jacob |last=de Gelder |location=’s-Gravenhage (The Hague) and Amsterdam |language=nl |year=1824 |pages=163–176 |publisher=de Gebroeders van Cleef |access-date=13 June 2017}}</ref>
|-
| [[Aubenas]], [[Ardèche]]
| canne
| align="right" | 8 ''pans''
| 	align="center"|1.985<ref name=kruger/>
|-
| [[Grand Duchy of Baden|Baden, Grand Duchy of]]
| Ruthe
| align="right" | 10 Fuß
| 	align="center"|3.0<ref name=kruger/>
|-
| [[Canton of Basel|Basel, Canton of]]
| Ruthe
| align="right" | 16 Fuß
| 	align="center"|4.864<ref name=kruger/>
|-
| [[Canton of Bern|Bern, Canton of]]
| Ruthe
| align="right" | 10 Fuß
| 	align="center"|2.932<ref name=kruger/>
|-
| [[Barcelona]]
| canna
| align="right" | 8 ''palmos''
| 	align="center"|1.581<ref name=kruger/>
|-
| [[Braunschweig]]
| Ruthe
| align="right" | 16 Fuß
| 	align="center"|4.565<ref name=kruger/>
|-
| [[Bremen]]
| Ruthe
| align="right" | 8 Ellen or 16 Fuß
| 	align="center"|4.626<ref name=kruger/>
|-
| [[Brussels]]
| Ruthe
| align="right" | 20 Fuß
| 	align="center"|4.654<ref name=kruger/>
|-
| [[Cagliari]], [[Sardinia]]
| canna
| align="right" | 10 ''palmi''
| 	align="center"|2.322<ref name=kruger/>
|-
| [[Calenberg|Calenberg Land]]
| Ruthe
| align="right" | 16 Fuß
| 	align="center"|4.677<ref name=kruger/>
|-
| [[Kassel|Cassel]], [[Hessen]]
| Ruthe
| align="right" | 14 Fuß
| 	align="center"|4.026<ref name=kruger/>
|-
| [[Denmark]]
| Ruthe
| align="right" | 10 Fuß
| 	align="center"|3.138<ref name=kruger/>
|-
| {{sortname|Canton of |Geneva|Canton of Geneva}}
| Ruthe
| align="right" | 8 Fuß
| 	align="center"|2.598<ref name=kruger/>
|-
| [[Hamburg]]
| Geestruthe
| align="right" | 16 Fuß
| 	align="center"|4.583<ref name=kruger/>
|-
| Hamburg
| Marschruthe
| align="right" | 14 Fuß
| 	align="center"|4.010<ref name=kruger/>
|-
| [[Kingdom of Hannover|Hannover]]
| Ruthe
| align="right" | 16 Fuß
| 	align="center"|4.671<ref name=kruger/>
|-
| [[France]]
| Perche
| align="right" | 3 ''[[toise]]s''
| 	align="center"|5.847<ref name=kruger/>
|-
| France
| Perche (for woodland)
| align="right" | {{frac|3|2|3}} ''toises''
| 	align="center"|7.145<ref name=kruger/>
|-
| [[Genoa]]
| canna
| align="right" | 10 ''palmi''
| 	align="center"|2.5<ref name=kruger/>
|-
| [[Jever]], [[Duchy of Oldenburg|Oldenburg]]
| Ruthe
| align="right" | 20 Fuß
| 	align="center"|4.377<ref name=kruger/>
|-
| [[Mallorca]]
| canna
| align="right" | 8 ''palmos''
| 	align="center"|1.714<ref name=kruger/>
|-
| [[Malta]]
| canna
| align="right" | 8 ''palmi''
| 	align="center"|2.08<ref name=kruger/>
|-
| [[Mecklenburg]]
| Ruthe
| align="right" | 16 Fuß
| 	align="center"|4.655<ref name=kruger/>
|-
| [[Menorca]], but not [[Mahón]]
| canna
| align="right" |
| 	align="center"|1.599<ref name=kruger/>
|-
| Menorca, city of Mahon
| canna
| align="right" | 8 ''palmos''
| 	align="center"|1.714<ref name=kruger/>
|-
| [[Messina]], [[Sicily]]
| canna
| align="right" | 8 ''palmi''
| 	align="center"|2.113<ref name=kruger/>
|-
| [[Montauban]], [[Tarn-et-Garonne]]
| canne
| align="right" | 8 ''pans''
| 	align="center"|1.783<ref name=kruger/>
|-
| [[Morocco]]
| canna
| align="right" | 8 ''palmos''
| 	align="center"|1.714<ref name=kruger/>
|-
| [[Naples]]
| canna (for cloth)
| align="right" | 8 ''palmi''
| align="center"|
|-
| [[Kingdom of Naples|Naples, Kingdom of]]: [[Apulia]], [[Calabria]], [[Eboli]], [[Foggia]], [[Lucera]]
| percha
| align="right" | 7 [[Palm (unit)|''palmi'']]
| 	align="center"|1.838<ref name=kruger/>
|-
| Naples, Kingdom of: [[Capua]]
| percha
| align="right" | {{frac|7|1|5}} ''palmi''
| 	align="center"|1.892<ref name=kruger/>
|-
| Naples, Kingdom of: Fiano, Naples
| percha
| align="right" | {{frac|7|1|2}} ''palmi''
| 	align="center"|2.014<ref name=kruger/>
|-
| Naples, Kingdom of: [[Caggiano]], [[Cava de' Tirreni|Cava]], [[Nocera Superiore|Nocera]], Rocce, [[Salerno]]
| percha
| align="right" | {{frac|7|2|3}} palmi
| 	align="center"|1.971<ref name=kruger/>
|-
| [[Nuremberg]], Bavaria
| Ruthe
| align="right" | 16 Fuß
| 	align="center"|4.861<ref name=kruger/>
|-
| [[Oldenburg (city)|Oldenburg]]
| Ruthe
| align="right" | 20 Fuß
| 	align="center"|5.927<ref name=kruger/>
|-
| [[Palermo]], Sicily
| canna
| align="right" | 8 ''palmi''
| 	align="center"|1.942<ref name=kruger/>
|-
| [[Parma]]
| Pertica
| align="right" | 6 [[braccio|''bracci'']]
| 	align="center"|3.25<ref name=kruger/>
|-
| [[Poland]]
| Pręt
| align="right" | {{frac|7|1|2}} ''łokci'' or 10 ''pręcików''
| 	align="center"|4.320<ref name=kruger/>
|-
| [[Prussia]], [[Rhine Province|Rheinland]]
| Ruthe
| align="right" | 12 Fuß
| 	align="center"|3.766<ref name=kruger/>
|-
| [[Rijnland]]
| Roede
| align="right" | 12 Voet
| 	align="center"|3.767<ref name="DeGelder1824"/>
|-
| [[Rome]]
| canna (for cloth)
| align="right" |
| 	align="center"|2<ref name=kruger/>
|-
| Rome
| canna (for building)
| align="right" |
| 	align="center"|2.234<ref name=kruger/>
|-
| [[Zaragoza|Saragoza]]
| canna
| align="right" |
| 	align="center"|2.043<ref name=kruger/>
|-
| [[Kingdom of Saxony|Saxony]]
| Ruthe
| align="right" | 16 Leipziger Fuß
| 	align="center"|4.512<ref name=kruger/>
|-
| [[Sweden]]
| Ruthe
| align="right" | 16 Fuß
| 	align="center"|4.748<ref name=kruger/>
|-
| [[Tortosa]]
| canna
| align="right" |
| 	align="center"|1.7<ref name=kruger/>
|-
| [[Grand Duchy of Tuscany|Tuscany, Grand-Duchy of]] ([[Florence]], [[Pisa]])
| canna
| align="right" | 5 bracci
| 	align="center"|2.918<ref name=kruger/>
|-
| [[Uzès]], [[Gard]]
| canne
| align="right" | 8 ''pans''
| 	align="center"|1.98<ref name=kruger/>
|-
| [[Vaud|Waadt, Canton of]]
| Ruthe or ''toise courante''
| align="right" | 10 Fuß
| 	align="center"|3<ref name=kruger/>
|-
| [[Württemberg]]
| Reichsruthe
| align="right" | 10 Fuß
| 	align="center"|2.865<ref name=kruger/>
|-
| Württemberg
| old Ruthe
| align="right" | 16 Fuß
| 	align="center"|4.583<ref name=kruger/>
|-
| [[Republic of Venice|Venice, Republic of]]
| Pertica
| align="right" | 6 ''piedi''
| 	align="center"|2.084<ref name=kruger/>
|-
| [[Canton of Zurich|Zürich, Canton of]]
| Ruthe
| align="right" | 10 Fuß
| 	align="center"|3.009<ref name=kruger/>
|-
|}

===In Britain and Ireland===
[[File:Gortavaura - geograph.org.uk - 1258792.jpg|thumb|Land for sale in Gortavaura, [[County Galway]], Ireland: the area is 48 acres, 3 [[rood (unit)|roods]] and 29 perches. In metric units, this is 19.8 [[hectares]].]]
In England, the rod or perch was first defined in law by the [[Composition of Yards and Perches]], one of the [[statutes of uncertain date]] from the late 13th to early 14th centuries: ''tres pedes faciunt ulnam, quinque ulne & dimidia faciunt perticam'' (three feet make a yard, five and a half yards make a perch).<ref>{{cite book |title=The statutes at large |location=London |publisher=Charles Eyre & [[Andrew Strahan]] |year=1794 |url=https://books.google.com/books?id=cKQ3AAAAMAAJ&pg=PA400 |page=200 |language=la}}</ref>

The length of the chain was standardized in 1620 by [[Edmund Gunter]] at exactly four rods.<ref name=Taylor/><ref name=Russell/> Fields were measured in acres, which were one chain (four rods) by one furlong (in the United Kingdom, ten chains).<ref name="dict-acre"/>

Bars of metal one rod long were used as standards of length when surveying land. The rod was still in use as a common unit of measurement in the mid-19th century, when [[Henry David Thoreau]] used it frequently when describing distances in his work, ''[[Walden]]''.<ref name="Thoreau1899"/>

In traditional [[Scottish units]], a ''Scottish rood'' (''ruid'' in [[Scots language|Lowland Scots]], ''ròd'' in [[Scottish Gaelic]]), also ''[[fall (Scots)|fall]]'' measures 222 inches (6 [[ell]]s).<ref>{{cite web |url=https://dsl.ac.uk/entry/dost/fall_n_1 |title="fall, faw" |website=Dictionary of the Scottish Language – [[Dictionary of the Older Scottish Tongue]]}}</ref>

==Modern use==
The rod was phased out as a legal unit of measurement in the United Kingdom as part of a ten-year metrication process that began on 24 May 1965.<ref name=dti/>
[[File:Indian Ovens (S) 2750.jpg|thumb|Sign near a historic site in [[Indiana]], with its location given as "80 rods east", equivalent to roughly 400&nbsp;m or {{frac|4}}&nbsp;mile.]]
In the United States, the rod, along with the chain, furlong, and statute mile (as well as the survey inch and survey foot) were based on the pre-1959 values for [[United States customary units]] of linear measurement until 1 January 2023. The [[Mendenhall Order]] of 1893 defined the yard as exactly {{frac|3600|3937}} meters, with all other units of linear measurement, including the rod, based on the yard. In 1959, an international agreement (the [[international yard and pound]] agreement), defined the yard as the fundamental unit of length in the Imperial/USCU system, defined as exactly 0.9144 metres. However, the above-noted units, when used in surveying, may retain their pre-1959 values, depending on the legislation in each state. The [[U.S. National Geodetic Survey]] and [[National Institute of Standards and Technology]] have replaced the definition for the above-mentioned units by the international 1959 definition of the foot, being exactly 0.3048 meters.<ref>{{cite web |title=NGS and NIST to Retire U.S. Survey Foot after 2022 |url=https://www.ngs.noaa.gov/web/news/us-survey-foot.shtml |website=National Geodetic Survey |access-date=4 March 2020 |date=31 October 2019}}</ref><ref>{{cite web |title=U.S. Survey Foot: Revised Unit Conversion Factors |url=https://www.nist.gov/pml/us-surveyfoot/revised-unit-conversion-factors |website=NIST |access-date=4 March 2020 |date=16 October 2019}}</ref>

Despite no longer being in widespread use, the rod is still employed in certain specialized fields. In recreational [[canoe]]ing, maps measure [[portage]]s (overland paths where canoes must be carried) in rods; typical canoes are approximately one rod long.<ref name="canoe1"/> The term is also in widespread use in the acquisition of [[pipeline transport|pipeline]] [[easement]]s, as the offers for an easement are often expressed on a "price per rod".<ref>{{cite web |url=http://www.pipelineattorney.com/learning-resources/pipeline-terminology.html |title=Pipeline Terms and Addendum |website=The Clark Law Firm |access-date=24 October 2012 |url-status=dead |archive-url=https://web.archive.org/web/20150308191248/https://pipelineattorney.com/learning-resources/pipeline-terminology.html |archive-date=8 March 2015}}</ref>

In the [[United Kingdom]], the sizes of [[allotment (gardening)|allotment]] [[garden]]s continue to be measured in square poles in some areas, sometimes being referred to simply as ''poles'' rather than ''square poles''.<ref name=allot/>

In [[Vermont]], the default [[right-of-way (transportation)|right-of-way]] width of state and town highways and trails is three rods {{convert|49|ft|6|in|abbr=on}}.<ref name=vermont/> Rods can also be found on the older legal descriptions of tracts of land in the [[United States]], following the "[[metes and bounds]]" method of land survey;<ref name=shelton/> as shown in this actual legal description of rural real estate: {{blockquote|LEGAL DESCRIPTION: Commencing 45 rods East and 44 rods North of Southwest corner of Southwest 1/4 of Southwest 1/4; thence North 36 rods; thence East 35 rods; thence South 36 rods; thence West 35 rods to the place of beginning, Manistique Township, Schoolcraft County, Michigan.<ref name="property"/>}}

=={{anchor|Area}}<!-- [[Square perch]] and [[Rod (area)]] redirect here-->Area and volume==
The terms ''pole'', ''perch'', ''rod'' and ''rood'' have been used as units of area, and ''perch'' is also used as a unit of volume. As a unit of [[area]], a ''square perch'' (the perch being standardized to equal {{frac|16|1|2}} feet, or {{frac|5|1|2}} yards) is equal to a '''square rod''', {{convert|30+1/4|sqyd|m2|2|abbr=off|lk=out}} or {{frac|160}} acre. There are 40 square perches to a [[Rood (measurement)|rood]] (for example a rectangular area of 40 rods times one rod), and 160 square perches to an [[acre]] (for example a rectangular area of 40 rods times 4 rods). This unit is usually referred to as a ''perch'' or ''pole'' even though ''square perch'' and ''square pole'' were the more precise terms. ''Rod'' was also sometimes used as a unit of area to refer to a rood.

However, in the traditional French-based system in some countries, 1 square ''perche'' is 42.21 square metres.

As of August 2013, perches and roods are used as government survey units in [[Jamaica]].{{cn|date=August 2024}} They appear on most property title documents. The perch is also in extensive use in [[Sri Lanka]], being favored even over the rood and acre in real estate listings there.<ref>{{cite web |url=http://www.srilankapropertymarket.com/LFS_page1.html |title=Land For Sale |website=Sri Lanka Property Market |url-status=dead |archive-url=https://web.archive.org/web/20180124203909/http://www.srilankapropertymarket.com/LFS_page1.html |archive-date=24 January 2018}}</ref> Perches were informally used as a measure in [[Queensland]] [[real estate]] until the early 21st century, mostly for historical gazetted properties in older suburbs.<ref>{{cite web |url=http://thebuzz.beesnees.com.au/tag/dutton-park-real-estate-agent/ |title=Dutton Park real estate agent Archives |website=Bees Nees}}</ref>

===Volume===
A traditional unit of volume for stone and other masonry. A perch of masonry is the volume of a stone wall one perch ({{convert|16+1/2|ft|m|2|disp=or}}) long, {{convert|18|in|cm|1}} high, and {{convert|12|in|cm|1}} thick. This is equivalent to exactly {{convert|24+3/4|cuft|cuyd m3 L|abbr=off}}.

There are two different measurements for a perch depending on the type of masonry that is being built:

#A dressed stone work is measured by the {{frac|24|3|4}}-cubic foot perch ({{convert|16+1/2|ft|m|2|disp=or}}) long, {{convert|18|in|cm|1}} high, and {{convert|12|in|cm|1}} thick. This is equivalent to exactly {{convert|24+3/4|cuft|cuyd m3|6|abbr=off}}.
#a brick work or rubble wall made of broken stone of irregular size, shape and texture, made of undressed stone, is measured by the ({{convert|16+1/2|ft|m|2|disp=or}}) long, {{convert|12|in|cm|1}} high, and {{convert|12|in|cm|1}} thick. This is equivalent to exactly {{convert|16+1/2|cuft|cuyd m3|6|abbr=off}}.<ref>See {{cite book |first1=William M. |last1=McClurg |first2=Morrell M. |last2=Shoemaker |name-list-style=amp |date=1970 |title=The Building Estimator's Reference Handbook |edition=17th |location=Chicago |publisher=Frank R. Walker Company |page=1644}}</ref>

==See also==
* [[Anthropic units]]
* [[English units]]

==References==
{{Reflist|refs=

<ref name=allot>{{cite web |url=http://www.watford.gov.uk/ccm/navigation/environment-and-planning/parks-and-open-spaces/allotments/ |title=Allotments |website=[[Watford Borough Council]] |access-date=5 October 2009 |url-status=dead |archive-url=https://web.archive.org/web/20090814005118/http://www.watford.gov.uk/ccm/navigation/environment-and-planning/parks-and-open-spaces/allotments/ |archive-date=14 August 2009}}</ref>

<ref name=bonten>{{cite web |url=http://home.kpn.nl/jhm.bonten/tables/anglosaxon/napolangsax.html#linsur |title=Anglo-Saxon and Biblical to Metrics Conversions |last=Bonten |first=JHM |date=19 January 2007 |at=Surveyor + Chain + British-Nautical |access-date=1 November 2010}}</ref>

<ref name="canoe1">{{cite web
| url=http://www.outdoorplaces.com/Features/Paddle/pickcanoe/newcanoe7.htm#rod
| archive-url = https://web.archive.org/web/20240203221120/http://www.outdoorplaces.com/Features/Paddle/pickcanoe/newcanoe7.htm#rod
| archive-date = 3 February 2024
| title=Canoe Glossary and Clickable Canoe
| website=OutdoorPlaces.com
| publisher=Michael Thiessen
| access-date=1 November 2010
}}</ref>

<ref name="dict-acre">{{cite encyclopedia
| url=http://www.unc.edu/~rowlett/units/dictA.html
| archive-url=https://web.archive.org/web/20081220111445/http://www.unc.edu/~rowlett/units/dictA.html
| url-status=dead
| archive-date=20 December 2008
| title=acre (ac or A)
| encyclopedia=How Many? A Dictionary of Units of Measurement
| last=Rowlett
| first=Russ
| publisher=University of North Carolina at Chapel Hill
| date=3 December 2008
| access-date=1 November 2010
}}</ref>

<ref name="dict-lug">{{cite encyclopedia
| url=https://www.ibiblio.org/units/dictC.html
| title=lug <nowiki>[1]</nowiki>
| encyclopedia=How Many? A Dictionary of Units of Measurement
| last=Rowlett
| first=Russ
| publisher=University of North Carolina at Chapel Hill
| date=15 December 2008
| access-date=1 November 2010
}}</ref>

<ref name=dti>{{cite report
 |url=http://www.metric.org.uk/Docs/DTI/met1968.pdf
 |title=Report (1968) by the Standing Joint Committee on Metrication
 |author=Consumer and Competition Policy Directorate
 |publisher=[[Department of Trade and Industry (United Kingdom)|Department of Trade and Industry]]
 |year=1968
 |access-date=1 November 2010
|url-status=dead
 |archive-url=https://web.archive.org/web/20080625230147/http://www.metric.org.uk/Docs/DTI/met1968.pdf
 |archive-date=25 June 2008
}}</ref>

<ref name="property">{{cite web
| url=http://www.eaglestar.net/ndu.html
| title=Lake View Parcel $198 Down $198 Month Incredible 8 Acre Parcel!
| work=EagleStar
| publisher=American Eagle Star
| access-date=1 November 2010
}}</ref>

<ref name=kruger>{{cite book |url=https://books.google.com/books?id=iro2AAAAMAAJ |last=Niemann |first=Friedrich |date=1830 |title=Vollständiges Handbuch der Münzen, Masse, und Gewichte aller Länder der Erde fur Kaufleute, Banquiers ... in alphabetischer Ordnung |trans-title=Complete handbook of coins, measures and weights of all countries in the world for merchants, bankers ... in alphabetical order |language=de |location=[[Quedlinburg]] und [[Leipzig]] |publisher=Gottfr. Basse |pages=[https://books.google.com/books?id=iro2AAAAMAAJ&pg=PA321 231]–232, 286}}</ref>

<!--REF NOT BEING USED IN ARTICLE
<ref name=nist>{{cite web |url=https://www.nist.gov/pml/wmd/h44-12.cfm |title=NIST Handbook 44 - 2012 Edition |first=Isabel |last=Chavez |date=26 October 2012 |website=nist.gov}}</ref>-->

<ref name=Russell>{{cite book|last1=Russell|first1=Jeffrey S.|author2=American Society of Civil Engineers|title=Perspectives in civil engineering: commemorating the 150th anniversary of the American Society of Civil Engineers|url=https://books.google.com/books?id=rOg6B38bunIC&pg=PA167|access-date=28 November 2011|date=1 August 2003|publisher=ASCE Publications|isbn=978-0-7844-0686-1|page=167}}</ref>

<ref name=shelton>{{cite web |url=http://www.homestead.org/NeilShelton/Legals/HowToReadLandDescriptions.htm |title=How to Read Land Descriptions |access-date=7 May 2008 |last=Shelton|first=Neil|website=homestead.org|page=5}}</ref>

<ref name=smith>{{cite book |url=https://books.google.com/books?id=uUPhhcdSACQC |first1=Sir William |last1=Smith |author1-link=William Smith (lexicographer) |first2=Charles |last2=Anthon |author2-link=Charles Anthon |name-list-style=amp |date=1851 |title=A new classical dictionary of Greek and Roman biography, mythology, and geography partly based upon the Dictionary of Greek and Roman biography and mythology |location=New York |publisher=Harper & Bros |pages=1024–1030}}</ref>

<ref name=Taylor>{{cite book|first=Thomas Ulvan |last=Taylor|title=Surveyor's hand book |url=https://books.google.com/books?id=swsEAAAAMAAJ&pg=PA1 |access-date=28 November 2011|year=1908|publisher=McGraw-Hill|page=1|chapter=Chapter 1}}</ref>

<ref name="Thoreau1899">{{cite book|last=Thoreau|first=Henry David|author-link=Henry David Thoreau|title=Walden: or, Life in the woods|url=https://books.google.com/books?id=jiE6AQAAIAAJ&q=rod |access-date=27 November 2011|year=1899|publisher=H. Altemus|pages=67, 113, 203, 204, 208, 290, 300, 309, 319, 339, 341, 356}}</ref>

<ref name=vermont>{{cite web |url=https://legislature.vermont.gov/statutes/section/19/007/00702 |title=19 V.S.A. § 702: Width of highways and trails |work=The Vermont Statutes Online |publisher=[[Vermont General Assembly]]}}</ref>
}}

{{Imperial units}}
{{United States Customary Units}}

{{DEFAULTSORT:Rod (Unit)}}
[[Category:Imperial units]]
[[Category:Units of length]]
[[Category:Customary units of measurement in the United States]]
[[Category:Obsolete units of measurement]]
[[Category:Units of measurement]]
[[Category:Area]]