See also Cheshire acre, Cornish acre, Cunningham acre, Irish acre, Rhynland acre, Scottish acre
In the English-speaking world, before 8th – 21st century, the principal unit of land area. At one time many different acres existed in England, and this acre was often called the “statute acre”, to indicate it was the one established by law, at least as early as the 14th century. In places like the United States, where only one kind of acre has ever been used, the word “statute” is usually omitted. The (statute) acre is:
In the United States, since the acre is a land measure it is currently based on the U.S. survey foot and not on the international foot. One acre is about 4,046.873 square meters.
A square plot of ground, 208.7 feet on a side, will cover an acre. An American football field, 360 feet by 160 feet, is about 1.3 acres; 12 high school basketball courts are a little more than 1 acre.
The acre was originally the amount of land that could be plowed in a single day with oxen, or actually, what could be done by midday, since refueling took all afternoon (the oxen had to be put out to pasture). Similar units of land area are found wherever animals are used for plowing. The German Morgen and Roman jugerum had much the same meaning.
Like many units of land area, the acre was first thought of as a piece of land having certain dimensions. An acre was 40 perches long and 4 perches wide. The length of the acre, 40 perches, was roughly the distance a team of oxen could plow before needing a breather (this furrow-long became the furlong, 220 yards). Ploughmen prefer long furrows, because turning the team is a cumbersome process.
A strip 40 perches long and 1 perch wide was called a rood (not to be confused with the rod, a name from the Saxon gyrd used by the 13th century as a synonym for the perch.) So an acre was 4 roods. Not until much later (the 16th century, according to R. D. Connor) did most people begin to think of the acre as so many square feet or square rods.
In actual use in the Middle Ages the size of the acre varied greatly, generally being larger in poor land than in good. In some contexts it was almost synonymous with “small holding.”
Another complicating factor is that there were a variety of perches. As you can see, the area of the acre depends on the length of the perch.
The king's rod or perch, however, remained constant for eight centuries at 16½ feet, and that perch set the size of the statute acre.
In 1979, Council Directive 80/181/EEC of the European Community1, governing standardization on metric units in the European Union, included an exception that permitted Ireland and the United Kingdom to continue using the acre for a limited time. The Council was supposed to set an end date by 31 December 1989. In 1989, the directive was amended to leave the setting of the date to the U.K. and Ireland. Finally in 2007 the exception was allowed to expire2, since Ireland had finished converting its land registration system to meters by the end of 1998, and the U.K. sometime afterwards. The acre is no longer legal in either country.
1. Council Directive of 20 December 1979 on the approximation of the laws of the Member States relating to units of measurement and on the repeal of Directive 71/354/EEC. On the web at http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CONSLEG:1980L0181:19791221:EN:PDF
2. Proposal for a Directive of the European Parliament and of the Council amending Council Directive 80/181/EEC on the approximation... On the web at http://europa.eu/eur-lex/lex/LexUriServ/LexUriServ.do?uri=COM:2007:0510:FIN:EN:PDF See item 6.
1
Statutum de Admensuratione Terre
Statute for the Measuring of Land
[Undated but attributed to the 33rd year of Edward I (1305), though the substance is older. The great bulk of the statute is given over to a lengthy list of pairs of lengths and widths of fields which, multiplied, make 160 square rods (one acre), beginning with 10 rods by 16 rods and ending at 80 rods by 2 rods. It then concludes, here translated from the Latin:]
And Be it Remembered, That the Iron Yard of our Lord the King, containeth three feet and no more. And a Foot ought to contain Twelve inches, by the right measure of this Yard measured; to wit, the Thirty-Sixth part of this Yard rightly measured maketh one Inch, neither more nor less. And Five Yards and a half make one Perch, that is Sixteen Feet and a half, measured by the aforesaid Iron Yard of our Lord the King.
Statutes of the Realm, vol. 1, page 206.
2
Some men will tell you that a plough cannot work eight score or nine score acres yearly, but I will show you that it can. You know well that a furlong ought to be forty perches long and four wide, and the king's perch is sixteen feet and a half; then an acre is sixty-six feet in width.
Walter of Henley's Husbandry, page 9. Written (in French) about 1280.
Because acres are not all of one measure, for in some countries they measure by the perch of eighteen feet, and in some by the perch of twenty feet, and in some by the perch of twenty-two feet, and in some by the perch of twenty-four feet,…
Anonymous. Seneschaucie, page 69. Probably written in the 1270's.
Elizabeth Lamond, editor and translator.
Walter of Henley's Husbandry, together with an anonymous Husbandry, Senschaucie and Robery Grosseteste's Rules.
London: Longmans, Green and Co., 1890.
For a more recent version, see
Dorothea Oschinsky.
Walter of Henley and Other Treatises on Estate Management and Accounting.
Oxford: Clarendon Press, 1971.
A list of some local values of the acre in Britain in the 18th century is given in the Second Report of the Commissioners... (1820, page 5).
In England, 11th – 19th century, a unit of length = 4 perches or rods, = 66 feet, the width of the original acre. In medieval documents it usually, if not always, appears as part of a qualifying phrase that indicates that the width is meant. For example:
“three acres wide”
#781 in Kemble, Codex Diplomaticus Aevi Saxonici.
“..iii acera bræda...”
Legis Æðelstan, IV 5.
“...ix acrae latitudine...”
Legis Hen I, cap. xvi.
In the 17th century this distance became the length of the surveyor's chain. This length is also the distance between wickets in cricket, and the width of the strip of land that could be acquired by eminent domain for a road in the less-developed parts of the British Commonwealth.
The acre survived as a 66-foot unit of length into the 19th century in Bedfordshire and Buckinghamshire. In Derbyshire it could be either 84 or 96 feet, while in Yorkshire as a unit of length the acre was 84 feet.1
1. Second Report. Page 6.
In England the acre was also a unit of tax assessment. As such, it was not strictly related to the actual dimensions of the property. The following terms are mostly used by modern scholars:
In Normandy, 13th – 15th centuries?, a unit of land area = 160 square perches (each perch of 22 pieds), = 77,449 square pieds, about 8172 square meters. This unit was probably brought back from England to Normandy in the years following the Norman invasion. Local variations were plentiful, varying with the length of the perch.
H. Navel (Commandant).
Recherches sur les anciennes mesures agraires normandes. Acres, vergées
et perches.
Caen: Jouan et Bigot, 1932.
| home | | | units index | | | search | | | your comments  | | | about | | | help | | |
Copyright © 2000-2009 Sizes, Inc. All rights reserved.
Last revised: 1 August 2009.