An Acre

There is a lot of speculation in the literature about just what was an acre.  It was alternately a measure of area, length, or taxation units, and varied in size from one to another.  

I came up through the ranks of Civil Engineers and earned my way through college as a surveyor, both for construction activities and for establishing boundaries.  It was always to work for a licensed surveyor of one kind or another, never having been myself licensed; yet it was I who did the work and the units and legal descriptions interested me.

Common sense became the rule for the definition of the huge area of land that comprises the United States.  After the original colonial boundaries had already been established using metes and bounds, the Township/Range method of describing land was put in place for the remainder.  

The basic unit of that system is the “Section”, a square one mile on a side; then the Township/ Range, comprised of thirty-six sections.  There are various anomalies  to be considered, not the least of which is spherical excess experienced on long lines due to the fact that the Earth is a sphere but that is one detail that we aren't considering here.

The Section, being a square mile, is by definition 640 acres.  Then the whole thing breaks down very simply into “Quarter Sections” being 160 acres, “Quarter-quarter Sections” being 40 acres, and when these are quartered again there is the 10 acre parcel which very conveniently is one-eighth a mile, or 660 feet, on a side.

This from Wikipedia: “Distances were always measured in chains and links, based on Edmund Gunter’s 66 foot measuring chain.  The chain—an actual metal chain—was made up of 100 links, each being 7.92 inches (201 mm) long.  Eighty Chains constitute one U.S. Survey Mile.” 

It is interesting to note that a convenient ten of these 66 foot chains produces a line one-eighth of a mile long or one side of a 10 acre parcel.  It is my belief that the 100 links were standardized but not intended to be used as a subdivision of the chain as would inches be of feet.

Coming at it a different way, a mile is 1600 meters and also 1760 yards, which just happens to divide into 110 yards (1/16^th of a mile) equaling 100 meters; keeping this in mind it is easy to translate distances.  When one examines the 660 feet, one can see that it is 220 yards or 200 meters because 110 yards is 100 meters (more or less.)  So, 200 meters is very close to 1/8th of a mile, the side of a 10 acre square.  The scientific number is 109.361 yards equals 100 meters.  

It can be seen that in the world of land area measurement for subdivision, the 10 acre lot is the basic unit of land and the acre a way of getting a more precise measurement where the boundaries may not be regular.