Some people eat, sleep and chew gum, I do genealogy and write...

Saturday, March 7, 2015

Understanding Real Property Legal Descriptions for Genealogy: Land Measurements

Gunter's chain photographed at Campus Martius Museum.
The way real property (land) is measured seems arbitrary, and if you are like me, it is difficult to visualize what is included in any particular unit of measurement. However, recognizing land areas and measurements are essential talents for genealogists who are doing any kind of historical research.

For example, here is a list of some of the more common methods of measurement:
  • acres 
  • square yards
  • square feet
  • fulongs
  • chains
  • kilometers
  • miles
There are, of course many more that could be added to the list. In reality, many of these methods are interrelated and by understanding the history, their relationship becomes evident. We recognize that there are two major divisions in the world of measuring things, including land; English and Metric. For the purposes of this post we really only need to deal with linear measurements and we can ignore weight, volume, temperature and speed. If we are talking about land, we can also ignore very small measurements such as centimeters and nanometers. Here are the two most common systems and their most common modern components:

  • inches
  • feet
  • yards
  • miles
  • millimeters (I know these are small but I have to start here anyway)
  • centimeters
  • meters
  • kilometers
Here is a quote from John Quincy Adams in a Report to the Congress in, 1821 as quoted in "A Brief History of Measurement Systems" from the NASA Technical Standards Program:
Weights and measures may be ranked among the necessaries of life to every individual of human society. They enter into the economical arrangements and daily concerns of every family. They are necessary to every occupation of human industry; to the distribution and security of every species of property; to every transaction of trade and commerce; to the labors of the husbandman; to the ingenuity of the artificer; to the studies of the philosopher; to the researches of the antiquarian; to the navigation of the mariner, and the marches of the soldier; to all the exchanges of peace, and all the operations of war. The knowledge of them, as in established use, is among the first elements of education, and is often learned by those who learn nothing else, not even to read and write. This knowledge is riveted in the memory by the habitual application of it to the employments of men throughout life.
If you want to dig into all sorts of old measurement units, you can see a list in the Wikipedia article on English Units. I am only going to discuss those units that are significant in genealogical research. Outside of the United States and historically in almost any country, the units of measurement may and often do vary from the current units used.

It is reported that many of the English measurement units were derived from body parts. This may be ultimately true in some instances, but many measurements are very ancient and it is possible that there are earlier systems of which we are no longer aware. Uniform measurement in England dates from around 1196 AD. Here is a list of some historic measurements and how they fit into the modern ones:
  • 12 lines = 1 inch 
  • 12 inches = 1 foot 
  • 3 feet = 1 yard 
  • 1760 yards = 1 mile 
  • 36 inches = 1 yard 
  • 440 yards = quarter mile 
  • 880 yards = half mile
  • 100 links = 1 chain 
  • 10 chains = 1 furlong 
  • 8 furlongs = 1 mile 
  • 4 inches = 1 hand 
  • 22 yards = 1 chain 
  • 5.5 yards = 1 rod, pole or perch 
  • 40 poles = 1 furlong
Here is how these measurements translate into area:
  • 144 square inches = 1 square foot 
  • 9 square feet = 1 square yard 
  • 4840 square yards = 1 acre
  • 1 furlong x 1 chain = 1 acre 
  • 1210 square yards = 1 rood 
  • 1 furlong x 1 pole = 1 rood 
  • 4 roods = 1 acre
  • 640 acres = 1 square mile
It is no coincidence that these measurement come out "even," they are related and exist because of the underlying measurements. You may also remember that a township is 36 square miles.

Here are the previous posts on Understanding Real Property Descriptions:


  1. Thanks for tables of equivalents.

    Any time a youngling seems uppity about their math abilities, suggest converting the speed of light into furlongs per fortnight.

  2. I just transcribed a deed that used chains. Thanks for sharing the photo and information!