Introduction to the Public Land Survey System

6th June 2007, 02:11 pm

The following is a very brief introduction to the Public Land Survey System of the United States. In the near future I will illustrate how genealogists can use this information to decipher old deeds and atlases. Hopefully someone will find this useful.

The Public Land Survey System (PLSS) is a system used in the United States to subdivide and identify parcels of land. Land is subdivided into Townships and Sections which can then be further subdivided as needed. It is sometimes referred to as the rectangular survey system.

Survey Control Lines

Two controlling survey lines are established: a baseline, running east-west and a principal meridian, running north-south. These two lines intersect at a known location called the initial point. There are 37 principal meridians, each with its own name. Baselines are generally unnamed. I do not know the history of how they were established, but to me they seem rather random. Check it out for yourself!

Townships

So we have an initial point from which to describe our land. Now what? Well, we establish lines every 6 miles starting from and parallel to the baseline. These are called township lines. Next, we establish lines every 6 miles starting from and parallel to the principal meridian. These are known as range lines. Now we have a nice, neat grid of land. Each chunk of land is 36 square miles (6 miles on each side) and is called a township.

Township Section Map

Each township is further divided into 36 sections which are (surprise!) one square mile each. These are numbered starting at the northeast corner. Sections 1-6 are numbered east to west, 7-12 are numbered west to east, and it continues to alternate with each row. Section 36, therefore, is in the southeast corner. See the figure from the General Land Office to the right.

Townships are indexed based on their position relative to the initial point. Township, range and section are abbreviated as T, R and S, respectively. I will use the example from wikipedia: S13-R20E-T1S MDM. This refers to Township 1 South, Range 20 East, Section 13, Mount Diablo Meridian. So, what exactly does this mean? Well, we start at the initial point on the Mount Diablo Meridian. Our township is in the first row of townships south of the baseline and the 20th township to the east of the Mount Diablo Meridian.

Sections may be further subdivided into quarter sections. This is usually where the federal government stops surveying. Further subdivision is done by private surveyors. Each quarter section may be chopped up as needed.

Here is a quick example of a legal description from my own research. The following is from Jasper County, IA Index to Deeds. Keep in mind that this is just a deed abstract.

Sumpter, William - DEEDED FROM - Shrew, Joel
SW fractional ¼ of Section 6 in Township 79 N of range 20 W in the district of lands subject to sale at Iowa City, Iowa containing 150 54/100 acres
Signed: Joel Shrew, Sarah Ann Shrew, 08 Nov 1853
$600.00; Book 3, Page 243b; Filed: 10 Dec 1853

We interpret the description from right to left. So the township is the one 20th west from the principal meridian and 79th north from the baseline. This description does not mention the name of the principal meridian, but a little research shows that this land is based off of the 5th Principal Meridian. Further, the land is the entire southwestern quarter of Section 6. Further research reveals that this is in Mound Prairie, Jasper County, IA.

This may all seem a bit confusing at first so I will give a few more examples in later articles. For a more in-depth look at the Public Land Survey System please see:

If you have any comments or suggestions please leave a comment and let me know how I can improve my random, sloppy writing!

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