lect23 USPLSS

The U.S. Public Land Survey System (USPLSS)

The USPLSS applies to most of the U.S. except for the thirteen original colonies, Texas, and Hawaii. This cadastral survey is the systematic basis for land subdivision in most of the country. One should be familiar with the system for land ownership reasons and because of the tremendous imprint it has left on the natural landscape. Link to this website (EcoAtlas) for a comparison with other survey techniques.

I. Brief History of the PLSS

Thomas Jefferson's report to Congress in 1784

called for surveys to be made before land sales
some system was needed to subdivide land promised to Revolutionary War soldiers and others
Jefferson wanted to avoid the difficulties of metes and bounds and provide an orderly system for parceling land.

1785 Land Ordinance

Called for townships consisting of 36 one square mile sections
Numbering of sections was from south to north and alternating to north to south in the next row. This system of notation is known as boustrophedonic (Grk.), meaning "turning like oxen in plowing."
Congress appointed surveyors for each state that work under the direction of the Geographer of the United States (first was Thomas Hutchins).
Surveyors had specific instructions regarding measurements and recording natural features of interest, e.g., minerals, salt licks, mill sites, water courses, etc.
Ohio (Northwest Territory) becomes the proving ground for the system

Land Act of 1796

changes numbering system of townships to east to west and then west to east, the system still in use.
subsequent legislation established sections as 640 acres

The Act of July 4, 1836 placed the responsibility for surveys with the General Land Office (GLO) where it remained until 1946 when the Bureau of Land Management was established.
Today, the Bureau of Land Management has the responsibility for cadastral surveying of federal and tribal lands.
Instructions are set out in a continual series of Survey Manuals. Currently, the 1973 manual is the standard.
The PLSS provided a straightforward method for cadastral surveying and land identification for millions of settlers and avoided many of the disputes inherent to metes and bounds systems. The appeal of land was a strong attraction to immigrants and others and the PLSS provided the method to divide the public domain (over 3,000,000 square miles).
This was a tremendous undertaking. Much of the country was unsettled and populated by understandably "not-too-happy" Native Americans. The public land surveyors were in many cases explorers of new regions. Until the early 1900s they were not government employees but contractors paid by the mile. In 1910, due in part to fraud, incompetence, and other factors, government surveyors (GLO) assumed the job from private contractors.
Early photo of a survey camp in Colorado.
Kansas Society of Land Surveyors (website with history and descriptions)
Brief History of Surveying in Colorado. Many good links.

II. How the system works (refer to this tutorial by the Wisconsin Department of Natural Resources). For specific information refer to the Manual of Surveying Instructions.

There are 31 principal meridians (north/south lines) and base lines (east/west) in the contiguous US (Figure 11.17 pp. 235, Map Use). The intersection of these lines is the initial point. Some meridians are numbered such as the Sixth Principal Meridian while others are named such as the New Mexico Principal Meridian.
Townships are numbered north or south of the base line
Ranges, or a "column" of townships are numbered east or west of the principal meridian. For example, T4N, R5E NM Principal Meridian is the fourth "row" of townships north of the BL and is in the fifth "column" east of the PM.
Initially, no allowance was made for convergence and accumulated error, however, after some modifications, this error is placed in the north and west portions of a township. In theory, each section (one square mile) contains 640 acres but errors and convergence may cause discrepancies.
Each 6 mile square township is divided into 36 sections (640 acres). Numbering begins in the NE corner section (1) and ends in the SE corner section (36). The numbers run in alternate lines east to west and then west to east, etc.
Each section may be subdivided into to smaller parcels (aliquot parts). For example, a ten acre parcel could be described as:

SE 1/4 SE 1/4 SE 1/4 sec. 5, T2N, R3W Boise Meridian, Idaho
Translated: the southeast quarter of the southeast quarter of the southeast quarter of section 5, Township 2 North, Range 3 West of the Boise Meridian. Description are read left to right but locating them is easier if one reads right to left or from larger division to smaller.
Each quadrant of section (NE, NW, SW, SE) can be subdivided in this method.
Further subdivision below 10 acres is usually by metes and bounds.
The Homestead Act of 1862 that granted 160 acres to a head of household was based on the PLSS. In other words, you would get a quarter section (1/4 of 640 acres).

Periodically, due to convergence (24 miles), township lines are adjusted. Every 24 miles from the base line a standard parallel or correction line is used to correct for longitudinal convergence. Adjustments are also made when the system contacts other survey systems such as earlier methods, tribal lands, land grants (e.g., Spanish grants in New Mexico), and bodies of water. In these cases the previous survey takes precedence and the section lines end at the boundaries of such.
The surveying manuals required specific monuments for township and section corners. Today, the BLM uses stainless steel pipe with a bronze cap (Cibola National Forest and Manzano Land Grant boundary) but earlier monuments can be stone, posts, or dirt mounds. When possible, corners are further referenced to bearing trees or other natural features. Witness and bearing trees and line blazes also help relocate points.
The chain is the unit of measurement for the PLSS. Although this unit may not be familiar to you, surveys of public lands retain this old unit. All measurement, except for some mineral and townsite surveys, use horizontal chain measurements.

1 chain=100 links or 66 feet
1 link=7.92 inches
80 chains=1 mile or 5280 feet
480 chains=6 miles or a township line
1 acre=10 square chains or 43560 square feet

Surveyors were and are required to keep detailed field notes and prepare plats of the survey. The plat is a legal document that establishes boundaries and ownership. Usually, in court, an original monument position, even one in error, takes precedence.
Glossary of survey terms.
Error and Accuracy importance.

III. The cultural imprint on the landscape

The portion of the country surveyed by the PLSS reflects the superimposed grid on the landscape. Roads and highways often follow section and township boundaries as do property lines. Remember, with few exceptions, this grid was blind to natural features. Lines continued over mountain ranges, deserts, and plains. One can see the imprint of this system, particularly in western states. For example, a land ownership map of a portion of Wyoming clearly exhibits the pattern of the PLSS. The effect of the system is quite apparent on the landscape and on maps and aerial photos.
Land ownership, i.e., federal, state, railroad, and private land takes on a "checkerboard" pattern determined by township and section lines.
Offsets in roads often occur at the correction lines or standard parallels (24 mile intervals).
Boundaries of national parks, wilderness areas, and other features frequently do not follow "natural" boundaries but instead follow PLSS survey lines.

IV. Field notes and plats as surrogate data

Surveyors were and are required to keep detailed field notes. In addition, to measurements they kept notes on topography, vegetation, timber, soils, mineral deposits, and other features. By using these data in the field notes, one can often reconstruct, at least qualitatively, past environments. For example, the area I work on in New Mexico was first surveyed in 1855-57. Based on these field notes and the surveyor's plats, I am reconstructing the patterns of vegetation change in the Manzano Mountains of central New Mexico. GISs are used then to create pattern maps.
A current example of field notes (requires Adobe Acrobat for .pdf files).
The problems with this technique is that surveys are often in error. One must approach data accumulated by contract surveyors with some amount of skepticism. Often their results were shoddy (Jack Daniel's surveys) if not downright fraudulent. Familiarity with different surveyors and the area helps minimize this concern.
Take a look at this study which attempts to reconstruct past vegetation patterns in Iowa.

References

Cazier, L. 1975. Surveys and surveyors of the public domain 1785-1975. Washington: US Government Printing Office.
White, C.A. ~1982. A history of the rectangular survey system. Washington: US Government Printing Office.
US Bureau of Land Management. 1973. Manual of instruction for the survey of the public lands of the United States. Technical Bulletin 6. Washington: US Government Printing Office.
Wisconsin State Cartographer's Office

Created 22 Oct 99. Revised 25 March 2002. D.J. Huebner, University of Texas at Austin, ©2002