Section (U.S. land surveying)

This article should be merged with  Section (land)

A section in U.S. land surveying is a parcel one mile square.

The importance of "sections" was greatly enhanced by the passage of the Northwest Ordinance of 1787 by the U.S. Congress. This law provided that lands outside the then-existing states could not be sold, otherwise distributed, or opened for settlement prior to being surveyed. (Many of the Founders were land surveyors and speculators, including especially George Washington.) The standard way of doing this was to divide the land into sections. An area six sections by six sections would define a township. Within this area, one section was designated as school land. As the entire parcel would not be necessary for the school and its grounds, the balance of it was to be sold with the monies to go into the construction and upkeep of the school.

The existence of section lines made property descriptions far more straightfoward than the old "metes and bounds" system. The establishment of standard east-west and north-south lines ("township" and "range lines") meant that deeds could be written without regard to temporary terrain features such as trees, piles of rocks, fences, and the like, and be worded in the style such as "Lying and being in Township 4 North; Range 7 West; and being the northwest quadrant of the southwest quadrant of said section," an exact description in this case of 40 acres, as there are 640 acres in a square mile. (The existence of such documents is a major reason why the U.S. will never be able to adopt the metric system in its entirety.)

In many jurisdictions, roads were run along every section line, giving access to previously remote areas and serving in many instances as firebreaks. In some locales, these lines were designated as the basis for a street numbering system; in Tulsa, Oklahoma, for example it can be correctly assumed that 190th Street is exactly seventeen miles beyond 20th Street, each "block" representing one-tenth of a mile.

The practice of dividing each section into quadrants and subdividing each quadrant into subquadrants made forty acres the standard "smaller" land division (the section being the larger one); this gave rise to the classic "Americanisms" "the back forty" and "the north forty" in reference to parcels of land that one might own or otherwise control.