Understanding Real Property Legal Descriptions for Genealogy: Rectangular Survey, Part One

Elements and units of the US Public Land Survey System: A) townships, B) sections, C) aliquot parts.
By Gretarsson (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

You may be familiar with the history of the first president of the United States, George Washington, but you may not be familiar with his early career as a surveyor and lifelong interest in maps, geography and cartography. See George Washington: Surveyor and Mapmaker from the Library of Congress. Quoting from this interesting article:

The George Washington Atlas, initially published in 1932 by the George Washington Bicentennial Committee, was the first attempt to compile a bibliography of maps drawn or annotated by George Washington. The atlas was conceived as part of the nationwide observance of the two hundredth anniversary of Washington's birth and identified 110 extant maps or surveys drawn or annotated by Washington.2 The editor, Colonel Lawrence Martin, chief of the Geography and Map Division, Library of Congress, attempted to list all known Washington maps and brought more than twenty new items to light. These range from Washington's first survey exercise in 1747 to his last survey of the Mount Vernon lands and include pencil sketches, pen and ink drawings, roughly drawn field surveys, and finished survey plats. Recent research has uncovered additional items not included in the 1932 inventory.3

Surveying and surveyors have been an integral part of our cultures and legal systems since ancient times. The current Public Land Survey System (PLSS), as illustrated above, is merely the most recent method of systematically mapping out land using a rectangular survey. Most recently, the system has been combined with GPS (Global Positioning System) to achieve a very high degree of accuracy. See "A History of the Rectangular Survey System, U.S. Department of the Interior, Bureau of Land Management."

From a genealogical standpoint, understanding rectangular surveys is extremely important. As I mentioned in my previous post on metes and bounds, genealogists are likely to find valuable information about the location of their ancestors from the following:

• deeds
• rental or lease agreements
• probate documents
• gifts or bequests
• sales contracts
• tax documents
• mortgages
• deeds of trust
• land warrants
• trust documents
• wills

and many other documents. 

Here is an example of the legal description of a piece of property using the PLSS or rectangular survey system:

. . . the following described property, situated in the Parish of Vernon, Louisiana, to-wit:- Southwest quarter of Southwest quarter (SW ¼ of SW ¼) and West Half of Southeast quarter of Southwest quarter (W½ SE¼ SW¼) of Section Eleven (11), Township Four (4) North of Range Eight (8) West, containing sixty (60) acres of land, more or less, together with the residence, garage, barns and garden used by J. H. Kurth, Jr. for the past ten (10) years, and also the garage building now being used as a pipe storage room, but there is excepted from this sale all other buildings and improvements on said property which are expressly reserved by the vendor.

A rectangular survey begins with the establishment of a base point. From when I was much younger, I knew there was a sandstone marker on the corner of South Temple and Main Street in Salt Lake City, Utah that marked the base point for the rectangular survey in Utah. Here is a photo from the Salt Lake County Surveyors Office:

Salt Lake Base and Meridian Monument on the Southeast Corner of Temple Square
Salt Lake County Surveyor's Office 

Many communities in the United States have a road or highway named "baseline road." This road usually closely follows the original survey line running east and west. In effect, the rectangular survey is really an extension of the worldwide system of using latitude and longitude to determine exact locations on the earth's surface.

The definition of latitude (φ) and longitude (λ) on an ellipsoid of revolution (or spheroid). The graticule spacing is 10 degrees. The latitude is defined as the angle between the normal to the ellipsoid and the equatorial plane.

Historically, because of the limitations in the equipment being used, rectangular surveys did not do a good job of taking into account the curvature of the earth. Over long distances, the surveys would often start to drift. I am very familiar with a location in Arizona where two rectangular surveys meet and the section boundaries are off by nearly a quarter of a mile. 

The idea of the rectangular survey is that a baseline is surveyed running east and west starting at a base point established by observing the position of the stars or in other words, astronomical observations. Anciently, the instrument used to determine a person's position on the spherical earth was an astrolabe. The more modern instrument is called a sextant. Here is an image of an astrolabe:

A 16th-century astrolabe, showing a tulip rete and rule

Here is an image of a sextant:

Quintant Sextant or Lattice Sextant. Manufactured by Spencer, Browning & Rust. In the collection of the United States Geological Survey Museum.

Once a base point has been established, the initial survey line is made by using an instrument that tells the direction of the line. Historically, this was accomplished with a compass. In more modern times, that function is accomplished with the use of an instrument called a transit or theodolite. Here is an image of a transit:

By en:User:Rolypolyman - Photo taken and uploaded by contributor. [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/)], via Wikimedia Commons

The transit or theodolite is used to establish a straight line from a certain point to be used in the measurement of a map or land boundary. After a baseline in defined and mapped, another line is established at a right angle to the original baseline. This north/south line is called the Meridian. If you look at the first image above, you will see a diagram illustrating the baseline and meridian. All other measurements are taken from the point at which the two lines intersect.

In my next post in this series, I will explain how to read a legal description of a rectangular survey. Tune in again for more on this valuable subject for genealogists.