in Louisiana

The French had ceded Louisiana to Spain by the Treaty of Fontainebleau (1762), but at the behest of Napoleon, Spain ceded it back by the Treaty of San Ildefonso (1 October 1800, confirmed by the Treaty of Madrid, 21 March 1801). Spanish administrators, however, continued to govern. Losing interest in a New World empire, Napoleon sold Louisiana to the United States (2 May 1803). The United States formally took possession on 20 December 1803.

While it was a French possession, and even under Spain, land grants were made in terms of arpents, and the word was used both (as in France) for the linear unit and the unit of area, the square arpent. Within the Louisiana Purchase, the arpent is mainly found in the present-day state of Louisiana and in the vicinity of St. Louis, Missouri.


In the urban portions of the state of Louisiana (USA), a unit of length, 18ᵗʰ – 20ᵗʰ centuries, approximately 58.47 meters (approximately 191.835 feet). It is the linear arpent de Paris = 10 perche de Paris, and is the same as the Canadian arpent.


In the rural portions of the state of Louisiana (USA), a unit of length, 19ᵗʰ – 20ᵗʰ centuries, 191.944 feet (approximately 58.504 meters).

An edict of Louis XV dated 12 October 1716 mentions that land in the Province of Louisiana will be granted in modules 2 to 4 arpents wide along the river by 40 to 60 arpents deep.

When the province was in Spanish hands, the Capitán-General authorized modules 6 to 8 arpents wide by 40 arpents deep (regulations issued 18 February 1770). In practice, the dimensions of the grants were often stated in lieue, and a number of different lieue were in use during this period. French and Spanish surveyors in Louisiana interpreted the lieue as 2500 toise de Paris, = 83 1/3 arpent de Paris instead of 84.

Following the Louisiana Purchase, the U.S. government sent surveyors to Louisiana who measured existing land grants, and, calculating backward, settled on a value of 191.994 feet exactly for the arpent.


Units of area. See source 1 below.


In a number of legal documents originating in Missouri the arpent is spelled “arpen,” a spelling which does not occur elsewhere. For examples, see source 4 below.



Whereas the baron of Carondelet, Governor General of the Territory of Louisiana, did, on the fifteenth day of March, anno Domini seventeen hundred and ninety-seven, instruct Zenon Trudeau, lieutenant governor of said territory, to place Moses Austin in possession of a league square of land at Mine a Breton, in said territory; and

Whereas the said Moses Austin did, in the year anno Domini seventeen hundred and ninety-eight, take possession of the said land by moving upon it with his family, and did improve the same by building dwelling house, blacksmith shop, furnace, and other improvements, and

Whereas, the said lieutenant governor did, on the fourteenth day of January, seventeen hundred and ninety-nine, order Antone Lulard, surveyor in said territory, to survey the said land and put the said Austin legally in possession of the same, which survey, numbered fifty-two, containing seven thousand one hundred and fifty-three arpents, and three and two-thirds feet, was executed by said Antone Lulard, and a certificate of the same filed by him in November, anno Domini eighteen hundred; and

Whereas Don John Ventura Morales, then Governor at New Orleans, did, in the year of our Lord eighteen hundred and two, in the name of the King of Spain, grant to the said Moses Austin the land so surveyed and located, therefore

Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled that the United States hereby release whatever title they have to said lands now numbered four hundred and thirty on the plat in the surveyor general's office, and in townships thirty-seven and thirty-eight, range two east, in the County of Washington and State of Missouri, containing seven thousand one hundred and fifty-three and thirty-two one-hundredths arpents (six thousand eighty-five and twenty-nine one-hundredths acres), to the heirs, legal representatives, or assigns of said Moses Austin, according to their respective interests therein, provided however that this act shall not affect nor impair the title which any settler or other person may have acquired adverse to the title of said Moses Austin to any portion of said land.

Act of Congress, 18 Stat. 16, February 14, 1874.
Chap. 29 An act to confirm certain land titles in the State of Missouri.

“League square” refers to a square lieue. The equivalence in the last paragraph makes 1 arpent equal to about 0.85 acre.


In the treaty of cession of Louisiana no exceptions were made, and this Court has declared that none can thereafter be made. 8 Pet. 463. The United States must remain content with that which contented them at the transfer when they assumed the precise position of the King of Spain. The United States has so remained, as appears by its laws. By the acts of 1804, 1805, 1807, and 1816, it recognized the laws, usages, and customs of Spain to be legitimate sources of titles, and by the act of 1812 confirmed to the inhabitants of St. Louis and other villages, according to their several right or rights of common thereto, the rights, titles, and claims to town or village lots, out lots, common field lots, and commons, in, belonging or adjoining to the same, which titles depended on parol grants and local customs. The same recognition extended to grants to actual settlers, pursuant to such laws, usages and customs; to acts done by such settlers to obtain a grant of lands actually settled, or persons claiming title thereto, if the settlement was made before 20 December, 1803.

Lying and being in the City and County of St. Louis, State of Missouri, containing two arpents in breadth, by forty in depth, or eighty superficial arpents, French measure, one of which arpents by forty was granted to one Rene Kiersereau and his heirs, by the proper authority, and the other, to-wit, the northern of said two arpents, was originally granted to one Gamache and his heirs, and which said two arpents by forty are bounded on the north by a forty-arpent lot originally granted to one Louis Bissonet, and on the south by a forty arpent lot, originally granted to one John Baptiste Bequette, and which said two forty arpent lots so above bounded have been confirmed by the authority of the Congress of the United States to the legal representatives of the said Rene Kiersereau and Gamache respectively.

By the evidence, it appears that in 1764, the post of St. Louis, in Upper Louisiana, was first established by the French under M. Laclede. In May, 1770, the Spaniards, under the treaty of 1762, took possession of St. Louis and Upper Louisiana. Between the year 1764, and 1772, divers grants of land in Upper Louisiana were made by the French and Spanish authorities, respectively. Amongst those grants were some forty or fifty, containing each from one arpent by forty, to four arpents by forty, located in the prairie immediately west of the then Village of St. Louis and extending some distance north and south of it. These lots extend westward to the uniform depth of forty arpents, being parallelograms whose opposite sides are on the north and south, forty arpents in length, and on the east and west from one arpent to four arpents.

Sometime in the year 1772 a survey was made, as above described, of these lots by Martin Duralde, the authorized surveyor of the post of St. Louis.

About that time, a fence was established on the eastern boundary of the above range of lots, which separated them from the village and what was called the commons; there was no division fence, nor any fence on the western boundary; the lots were contiguous to each other, but each lot was held separately and cultivated separately by its proprietor or occupant, who was bound by the regulations of the post to keep the fence in front of his lot (or of whatever number of lots he occupied) in good repair.

The surveys so made by Duralde were entered in a book called the Livre Terrein.

Amongst the lots so surveyed and entered are the two lots in question, described and bounded as in the declaration in this cause. The surveys so entered, and the grants by virtue of which said surveys were made, were solemnly recognized and affirmed by the Spanish lieutenant governor, Don Pedro Piernas, and by his predecessor, the French commandant, S'Ange de Bellerive.

The entry in the Livre Terrein, No. 2, p. 68, which contains this recognition of said grants and surveys, has been printed by authority of Congress, and is to be found in Gales & Seaton's American State Papers, vol. 3, 677. In the entry in the Livre Terrein of the survey of Gamache's arpent, the grantee is called 'Joseph' Gamache. This was a mistake, as is shown fully by the evidence in the cause. It is conclusively proved that the name of Gamache, the grantee, was John Baptiste Gamache, and that no such man as 'Joseph' Gamache existed at that time in Upper Louisiana.

Strother v. Lucas, 37 U.S. 12 Pet. 410 (1838)


They also read in evidence the following documents:

1. A copy, certified under the hand and seal of the Register of Lands for the State of Missouri, of

“the plat of survey No. 52, containing 7,153 arps. 32 2/3 p's, in the right of Moses Austin, as the same appears of record in first part of registre d'arpentage, page 85, Soulard's surveys, together with field notes of the same,”

Bryan v. Kennett, 113 U.S. 179 (1885)

Note the abbreviations for arpents and pieds.


Also a transcript of opinion, and report of the recorder of land titles of the United States at St. Louis, made 1 November, 1815, which, in connection with Act of Congress of 29 April, 1816, entitled, “An act for the confirmation of certain claims of land in the Western District of the State of Louisiana and in the Territory of Missouri” (see sec. 2 of this act), shows that the confirmation of 200 arpens, parcel of the claim of John Robertson, Jr., for 750 arpens of land in the Big Prairie, made by the board of commissioners aforesaid, was extended to 640 acres, and this quantity, 640 acres, was accordingly confirmed to him. Also a deed from John Robertson, Jr., to Edward Robertson, Sr. dated 29 May, 1809, conveying the said 750 arpens of land to the said Edward Robertson, Sr., in fee; reciting in same conveyance that 330 arpens of the said 750 arpens had been surveyed, and how, and specifying the manner of laying off the residue, and authorizing the said Edward Robertson to apply for and receive from government or the proper authorities, a patent in his own name for same, and covenanting on behalf of himself and his heirs, to warrant the title.

Long v. O'Fallon, 60 U.S. 19 How. 116 116 (1856)

In 1799, the Spanish government surveyed for Antoine Morin a tract of land, fronting on the Mississippi River, supposed to be sixteen arpens in front, having a depth of forty arpens, which, in February, 1809, was confirmed to his widow and heirs, he being then dead. The survey showing, however, that the tract contained more than 640 arpens, that quantity only was confirmed, and the commissioners directed another survey to be made so as to throw off the surplus on the western side of the tract.


The land was three arpens in front by forty in depth, and was nearly or quite identical with the land thrown out as above mentioned.

Bagnell v. Broderick, 38 U.S.13 Pet. 436 436 (1839)

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