Government Survey Descriptions

Overview#

The United States System of Rectangular Surveys, commonly known as the Public Land Survey System (PLSS), provides a standardized method for identifying land within the public domain. Established by the Land Ordinance of 1785, the system divides land into a hierarchy of rectangular units -- principal meridians and baselines, townships, ranges, sections, and aliquot parts -- that can be combined to describe any parcel within the surveyed area.

Government survey descriptions are concise, systematic, and self-indexing. A description like "the northeast quarter of Section 10, Township 2 North, Range 5 East, of the San Bernardino Meridian" identifies exactly one parcel of approximately 160 acres without the need for metes-and-bounds courses, recorded maps, or any other supporting documentation.

"The use of sections, quarter sections and lots in sections with the township and range numbers and the name of the Meridian for the total area embraced make the description of land much easier and faster. Interestingly too, this method provides a self-sufficient non-duplicating vehicle for indexing such land." -- Wattles, Writing Legal Descriptions (1976), Ch. 1, p. 1.3

The system covers approximately 30 states -- generally those west of the Appalachian Mountains and south of the Great Lakes, excluding the original thirteen colonies, Texas, and Hawaii. For land within the PLSS, government survey descriptions are the primary method, often supplemented by metes and bounds when irregular or partial parcels must be described.

The PLSS Framework#

Principal Meridians and Baselines

The PLSS is organized around 37 principal meridians and their associated baselines. Each principal meridian runs north-south, and its baseline runs east-west. Together they establish the origin point for a grid of townships and ranges.

Townships and Ranges

Townships are nominally six miles square. They are identified by their position relative to the baseline (Township 1 North, Township 2 South, etc.) and their position relative to the principal meridian (Range 1 East, Range 2 West, etc.).

"Standard parallels and township boundaries are given precedence over subdivisional lines." -- Wattles, Writing Legal Descriptions (1976), Ch. 13, p. 13.2

Sections

Each township is divided into 36 sections, each nominally one mile square (640 acres). Sections are numbered 1 through 36 in a serpentine pattern starting in the northeast corner.

Aliquot Parts

Sections are subdivided into halves and quarters. Quarter sections are further subdivided into halves and quarters, and so on. These subdivisions are called "aliquot parts" because they represent exact fractional divisions of the section.

The Description Format#

A government survey description follows a specific order of elements:

"The subject matter used in a section type description should be arranged in the following order: Lot Number (if any), Section (or part of), Township (North or South), Range (East or West), Meridian, City (if any), County (or Parish or Borough), State, Reference to the Official Plat." -- Wattles, Writing Legal Descriptions (1976), Ch. 13, p. 13.9

A complete example:

Lot 1, Section 4, Township 3 North, Range 2 East, of the First
Principal Meridian, in the County of Oshkosh, State of Dakota,
according to the official plat of said land filed in the District
Land Office.

Reading Aliquot Descriptions#

A critical skill -- and a frequent source of error -- is reading aliquot part descriptions. The convention is to read the description from right to left (or, equivalently, from the largest subdivision to the smallest). The last-named subdivision is the largest area, and each preceding term narrows the location within it.

Worked Example 1: Simple Quarter-Quarter

Description: "The NE 1/4 of the SW 1/4 of Section 10, T2N, R5E, SBM"

Reading right to left:

1. Start with Section 10 in Township 2 North, Range 5 East
2. Locate the SW 1/4 of that section (the southwest quarter)
3. Within the SW 1/4, locate the NE 1/4 (the northeast quarter of that quarter)

The resulting parcel is 40 acres (nominally):

$\frac{1}{4} \times \frac{1}{4} \times 640 \text{ acres} = 40 \text{ acres}$

Worked Example 2: Half-Quarter

Description: "The S 1/2 of the NW 1/4 of Section 22, T1S, R3W, MDM"

Reading right to left:

1. Start with Section 22
2. Locate the NW 1/4 (northwest quarter = 160 acres nominally)
3. Within the NW 1/4, take the S 1/2 (south half)

$\frac{1}{2} \times \frac{1}{4} \times 640 \text{ acres} = 80 \text{ acres}$

Worked Example 3: Complex Aliquot

Description: "The W 1/2 of the SE 1/4 of the NE 1/4 of Section 5, T4N, R7E, WM"

Reading right to left:

1. Start with Section 5
2. Locate the NE 1/4 (160 acres)
3. Within that, locate the SE 1/4 (40 acres)
4. Within that, take the W 1/2 (20 acres)

$\frac{1}{2} \times \frac{1}{4} \times \frac{1}{4} \times 640 \text{ acres} = 20 \text{ acres}$

Worked Example 4: Multiple Aliquot Parts

Description: "The NE 1/4 and the N 1/2 of the SE 1/4 of Section 15, T3S, R2E, SBM"

This describes two separate parcels treated as one:

• The NE 1/4 = $\frac{1}{4} \times 640 = 160$ acres
• The N 1/2 of the SE 1/4 = $\frac{1}{2} \times \frac{1}{4} \times 640 = 80$ acres

$\text{Total} = 160 + 80 = 240 \text{ acres}$

Fractional Lots#

Not all land within a section divides neatly into standard aliquot parts. When sections border rivers, lakes, township boundaries, or other irregular features, the irregular portions are designated as numbered lots on the official township plat.

"When a section does not contain the regular 640 acres, as in the west tier or north row in a township, the odd areas are assigned lot numbers." -- Wattles, Writing Legal Descriptions (1976), Ch. 13, p. 13.7

Lots in sections are "whole" lots, not to be confused with the lots on private subdivision maps. They are numbered on the official township plat and are described by their lot number along with the section, township, range, and meridian.

Fractional sections occur in several situations:

• Sections along the north and west boundaries of a township absorb the excess or deficiency caused by the convergence of meridians
• Sections cut by rivers, lakes, or other natural features are subdivided into lots along the irregular boundary
• Sections at the boundaries between different principal meridian systems may have irregular shapes

When a description must combine a fractional lot with a standard aliquot part, both are listed:

Lot 2 and the SE 1/4 of the NW 1/4 of Section 6, Township 3 North,
Range 4 East, of the Willamette Meridian...

The Section as the Basic Unit#

The section is the fundamental building block of government survey descriptions. Understanding what a section actually is -- as opposed to what it theoretically should be -- is essential for writing and interpreting descriptions correctly.

"Too often the assumption is accepted that a section is just one mile square and that therefore the quarter section is 2640 feet by 2640 feet... It is an extremely rare case when a section line between correct monuments is measured exactly 5280 feet or 2640 feet to the quarter section monument." -- Wattles, Writing Legal Descriptions (1976), Ch. 13, p. 13.4

In practice, sections vary from the theoretical dimensions. Some vary by a few feet; others by hundreds of feet or more. Wattles notes extreme examples:

"In fact, one particular Section 6 is a mile and one half east-west, while in another area, a certain Section 3 is over a mile and one half north-south." -- Wattles, Writing Legal Descriptions (1976), Ch. 13, p. 13.4

This variation arises from the accumulated errors of the original surveys, the convergence of meridians, and the practical difficulties of running lines through difficult terrain with the instruments of the 18th and 19th centuries.

Subdivision of Sections

The rules for subdividing sections into aliquot parts are defined in the BLM Manual of Surveying Instructions. The fundamental rule is:

• Quarter section corners are located at the midpoints of the section boundaries (connecting opposite quarter-section corners with straight lines)
• Interior quarter-quarter section corners are located at the midpoints of the quarter-section boundaries
• Even if the section is distorted, the subdivision follows the rule of connecting opposite quarter corners through midpoints

"The division into halves and quarters must follow the rule of connecting opposite quarter corners." -- Wattles, Writing Legal Descriptions (1976), Ch. 13, p. 13.5

This means that the actual dimensions of an aliquot part depend on the surveyed dimensions of the section, not on theoretical values. A "40-acre" quarter-quarter section might actually contain 38 or 42 acres depending on the section's actual proportions.

Protracted vs. Surveyed Subdivisions#

The interior subdivisions of a section -- the quarter-section and quarter-quarter-section lines -- may be either surveyed (actually run on the ground by the original government surveyor) or protracted (shown on the official plat but not actually surveyed).

For protracted subdivisions, the lines are established by computation according to the Manual rules, using the surveyed section corners and quarter-section corners as control. The private surveyor performing a retracement must apply the correct rules for the era of the original survey.

"Remember that the date of the Manual or Pamphlet applies to the work done following that date and prior to the next issue." -- Wattles, Writing Legal Descriptions (1976), Ch. 13, p. 13.4

The BLM Manual that was in effect at the time of the original survey governs the rules for that survey. A section first subdivided under the 1855 Manual follows different tolerance standards than one subdivided under the 1973 Manual.

Common Errors in Government Survey Descriptions#

1. Assuming Theoretical Dimensions

The most common error is computing parcel boundaries using theoretical dimensions (2640 feet to a quarter corner, 1320 feet to a sixteenth corner) instead of applying the actual surveyed monument positions. The scrivener should not rely on subdividing the section on paper.

"The scrivener should be apprised of the fact that he should not rely on subdividing the section on paper because in all probability a resurvey on the ground in conformance with the rules will disclose any number of differences." -- Wattles, Writing Legal Descriptions (1976), Ch. 13, p. 13.4

2. Reading Aliquot Parts in the Wrong Direction

Reading "NE 1/4 of the SW 1/4" as the southwest quarter of the northeast quarter reverses the location within the section. The description must be read from right to left.

3. Duplicate Lot Numbers

Some approved township plats carry duplicate lot numbers within the same section. Wattles provides an example where both the NW 1/4 and the NE 1/4 of a section each contain a "Lot 1" and a "Lot 2." In such cases, the description must be carefully worded to identify which lot is intended:

"Because both of the areas labeled LOT 1 are shown as containing 80 acres, which is regular for the south half of the northwest quarter and the south half of the northeast quarter, neither one was required to be assigned a lot number." -- Wattles, Writing Legal Descriptions (1976), Ch. 13, p. 13.12

When duplicate lots exist, adding the aliquot part location resolves the ambiguity: "Lot 1 in the NW 1/4 of Section 6."

4. Confusing Government Lots with Subdivision Lots

Government lots (numbered lots on the official township plat) are fundamentally different from lots on private subdivision maps. They have different numbering conventions, different legal authorities, and different rules of interpretation. A description citing "Lot 3" must make clear whether it references the official township plat or a private subdivision map.

5. Omitting the Meridian

The meridian is essential for a complete PLSS description. "Section 10, Township 2 North, Range 5 East" is ambiguous because those coordinates exist in multiple principal meridian systems. The meridian must always be stated.

Combining PLSS and Metes and Bounds#

When a portion of an aliquot part must be described, the PLSS designation serves as the caption and metes-and-bounds courses provide the body:

That portion of the southwest quarter of the northeast quarter of
Section 12, Township 4 South, Range 2 East, of the Navajo Meridian,
State of Arizona, described as follows:

Beginning at the northwest corner of said quarter-quarter section;
thence S 89 36' E 660.00 feet along the north line thereof;
thence S 0 24' W 330.00 feet; thence N 89 36' W 660.00 feet
to the west line of said quarter-quarter section; thence N 0 24' E
330.00 feet to the point of beginning.

"If you have only a part of this, the form will be thus: 'That portion of the southwest quarter of the northeast quarter of Section....' continuing with: 'described as follows:' and then add the body of metes and bounds." -- Wattles, Writing Legal Descriptions (1976), Ch. 13, p. 13.10

The caption limits the conveyance to the specified aliquot part, even if the metes-and-bounds courses extend beyond it.

Area Calculations for Aliquot Parts#

The theoretical area of any aliquot part can be computed by multiplying the fractions:

These are theoretical values only. Actual areas depend on the surveyed dimensions of the section. For fractional sections, the actual area is shown on the official township plat. For regular sections that do not match the theoretical dimensions, the actual area of each aliquot part must be computed from the surveyed corners.

The general formula for the theoretical area of a nested aliquot part is:

$A = 640 \times \prod_{i=1}^{n} f_i \text{ acres}$

where $f_i$ is the fraction at each level of subdivision (1/2 or 1/4).

Key Takeaways#

• Government survey descriptions use the PLSS framework: section, township, range, and principal meridian. They are concise, self-indexing, and apply to approximately 30 states.
• Aliquot parts subdivide sections into halves and quarters. Read descriptions right to left -- the last-named term is the largest area, and each preceding term narrows the location.
• Theoretical dimensions (2640 ft to a quarter corner, 640 acres per section) are rarely matched in the field. Always use actual surveyed monument positions rather than theoretical values.
• Fractional lots are numbered areas on the official township plat that arise where sections border irregular features or absorb convergence. They are distinct from private subdivision lots.
• Protracted subdivisions were not surveyed on the ground. Interior lines are established by computation from surveyed corners, using the rules of the Manual in effect at the time of the original survey.
• Combined descriptions use the PLSS designation as a caption with metes-and-bounds courses in the body. The caption limits the area of conveyance.
• Common errors include assuming theoretical dimensions, reading aliquot parts in the wrong direction, confusing government lots with subdivision lots, and omitting the principal meridian.
• The BLM Manual that governs the survey is the one in effect at the time the original survey was executed, not the current edition.

References#

1. Wattles, G.H. Writing Legal Descriptions (1st Ed.). Rancho Cordova, CA: Landmark Enterprises, 1976. Chapters 1 and 13.
2. U.S. Department of the Interior, Bureau of Land Management. Manual of Surveying Instructions (2009). Chapters 3--7.
3. U.S. Department of the Interior, Bureau of Land Management. Restoration of Lost or Obliterated Corners and Subdivision of Sections (2009 reprint).
4. Robillard, W.G. & Wilson, D.A. Brown's Boundary Control and Legal Principles (7th Ed.). Hoboken: Wiley, 2014. Chapters 14--17.
5. Robillard, W.G. & Wilson, D.A. Evidence and Procedures for Boundary Location (6th Ed.). New York: Wiley, 2011. Chapters 10--12.