acre

In many languages the word retains its primitive sense, an open, plowed, or sowed field. In English, it retained its original signification, that of any open field, until it was limited to a definite quantity by statute. A piece of land, containing 160 square rods or perches, or 4840 square yards, or 43,560 square feet. This is the English statute acre. That of the United States is the same. — Webster, 1882

“An acre means the day’s work of a plough…. A good plough covers with a day’s work a stripe of land 22 yards wide and 220 yards long, which on water would be called 11 fathoms wide and 110 fathoms long. Or if turned into feet it would be 66 feet wide and 660 feet long. That is an Acre.” — J. Scott Russell, Geometry in Modern Life (London: Simpkin, Marshall, and Co., 1878), 48-49.

     
Tooltip TextOne acre is equal to the following units, among others: 66 feet by 660 feet, 4840 square yards, 10 square chains (a chain is 66 feet in length; the chain was commonly used in surveying land).

An acre was originally the amount of land that could be plowed in a single morning by a team of oxen. The oxen wouldn’t work in the afternoon; they would graze and thus refuel in order to be ready to plow again the next morning. It wasn’t until the 16th century that the acre came to be thought of in geometric terms, or length by width. A furlong was the typical unit of length, as this was roughly the distance of a furrow a team of oxen could pull a plow before having to stop and take a breather. This furrow-long became the furlong, or 200 yards. Plowmen prefer longer furrows, as turning a team is a cumbersome task.

In Little Town on the Prairie (Chapter 6, “The Month of Roses”), Laura Ingalls Wilder wrote that “the law was that a man could not keep a homestead claim unless his family lived on it, six months of every year for five years. Also he must keep ten acres of the sod broken up and planted to crops for five years, before the Government would give him a title.”

According to Charles Ingalls’ homestead file, he planted sixty acres in crops for each of six consecutive years prior to final proof. The image at left shows a satellite view of the Ingalls homestead that has been divided into 160 1-acre parcels.

The memorial marker and cottonwood trees are in the northwest corner of the homestead. A replica claim shanty stands approximately where the Ingallses’ shanty stood. In Pioneer Girl, Wilder wrote that Pa built the shanty on a low rise east of the barn, which was nestled into the eastern slope of the sand hill on the northwest corner of the claim. The area outlined in red shows five acres plowed and/or planted at the time the photograph was taken; note that the field is a furlong in length. When the Ingalls family lived on the homestead, over one-third of it was planted in crops.

The acre is a measurement of area, not shape. Since medieval times, the acre has never had specific dimensions; it is simply any piece of land containing 43,650 square feet. An acre may be long and skinny, square, or oddly-shaped. Using the same scale as the image above left, the shapes shown here are each one acre in size.

     

acre
(FB 15, 21; BPC 25; SSL 1, 25, 29, 31; TLW 23, 27; LTP 2, 6; THGY 19, 29, 30; PG)