Rectangular System

The PLSS or rectangular system of public land survey is used in 30 states. The system was adopted in 1785 by the Continental Congress to subdivide new lands northwest of the Ohio River in a logical and systematic manner. In general, the system establishes a grid by dividing the land by north and south line that follows a true meridian, with a base line that follows a latitude, see Figure 14.1.

Additional lines parallel to the base line, called standard parallels and lines perpendicular to the base lines, called guide meridians, are added to form quadrangles 24 miles square. A few of the original PLSS surveys laid out the lines 30 miles apart. A spacing of 24 miles became the later standard. In this discussion, we will

FIGURE 14.2. Rectangular system of public surveying.

consider only the 24-mile rectangular surveys. The quadrangles are divided into townships that are 6 miles square. The townships are further divided into 36 sections of approximately 640 acres each and each section is still further subdivided into fractional parts.

Because meridians converge, at the poles, it is mathematically impossible to have a true grid. A system of subdivisions was used to adjust for the converging of the meridians. This is the reason the guide meridians, Figure 14.2, are not continuous, but have an adjustment at each standard parallel. A description of the subdivisions follows:

1. Quadrangles: These square tracts are approximately 24 miles on each side.

2. Townships: Each quadrangle contains 16 townships, each approximately 6 miles on a side.

3. Sections: Each township is divided into 36 sections, each approximately one mile on a side and containing 640 acres.

4. Quarter sections: Each section is divided into quarter sections approximately one-half mile on a side and containing 160 acres. Quarter sections may be divided into fractional areas, the individual tracts containing 80,40,20,10, or 5 acres or combinations of these sizes.

The intent was to produce sections of land one mile to a side. Any variation because of convergence is placed in the western column and the top row of each township.

To begin an original survey, an initial point was established in each new area of land by astronomical observations. Thirty seven initial points were eventually established. A base line, a true parallel of latitude that extends in an east-west direction, and a principal meridian, a true north-south line, passes through each initial point. The principal meridian may be designated by name or by number. The Oklahoma Territory was surveyed from two different meridians, the Indian Meridian and the Cimarron Meridian. The territory that became the states of Kansas, Colorado, and Nebraska was also surveyed from the Indian Meridian, but in these states it was called the 6th Prime Meridian. Figure 14.2 illustrates the rectangular system.

In Figure 14.2, find the initial point, base line, and principal meridian. Note that quadrangles are bounded on the north and the south by true parallels of latitude, called standard parallels, which are 24 miles apart and are numbered consecutively north and south of the base line. For example, the First Standard Parallel North is 24 miles north of the base line, and the Fourth Standard Parallel North is 96 miles north of the base line. The east and west boundaries of quadrangles follow true meridians but because of the adjustment for convergence they are not continuous, therefore they are called guide meridians. They are 24 miles apart and are numbered consecutively east and west of the principal meridian. Thus, the First Guide Meridian West is 24 miles west of the principal meridian, and the Third Guide Meridian East is 72 miles east of the principal meridian.

Because the guide meridians are true meridians, they converge as they approach the North Pole and the South Pole. This causes the north side of each quadrangle to be slightly less than 24 miles. To adjust for convergence, a closing corner is set at the intersection of each guide meridian and each standard parallel or base line. The distance between the closing corner and the standard corner causes an offset in the meridian.

Townships are bounded on the north and the south by township lines and on the east and west by range lines. Range lines are true meridians and thus converge. The south boundary of each township is 6 miles in length, but the north boundary is slightly less. Closing corners are established for townships in the same way that they are established for quadrangles. Township lines are parallel to the base line and the standard parallel.

A township is identified by a unique description based upon the principal meridian governing it. A north-south column of townships is called a range. Ranges are numbered in consecutive order east and west of the principal meridian. An east-west row of townships is called a tier. Tiers are numbered in order north and south of the base line. By common practice, the word "tier" usually is replaced by "township" or just "T" in designating the rows.

An individual township is identified by its number and direction north or south of the base line, followed by the number and direction east or west of the principal meridian. The township designation usually is abbreviated, as for example, "T5N, R3E" of the prime meridian. This township would be located between 24 and 30 miles north and 12 and 18 miles east of the initial point. Figure 14.3 shows a quadrangle divided into townships and one township divided into sections.

3rd Parallel North

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2nd Parallel North FIGURE 14.3. Division of quadrangle and township.

2nd Parallel North FIGURE 14.3. Division of quadrangle and township.

Based on the earlier discussion, the township divided into sections in Figure 14.3 would be identified as, T10N, R6E.

Figure 14.4 shows the method of subdividing a township into 36 sections, one mile square (640 acres). Sections are numbered by starting in the northeast corner of the township and continuing in a serpentine fashion. If the survey is error free, which is extremely improbable, all sections are one mile square except those along the west and north boundary of the township. These sections are less than one mile in width because of convergence of the range lines and any error in measurements. The description of the highlighted section in Figure 14.4 is "S21," and the township identified in Figure 14.3 is T10N, R6W, Principal Meridian (or PM). "The complete description would be written as, "S21, T10N, R6W, PM."

FIGURE 14.4. Section numbers in township.

FIGURE 14.5. Subdivision of a section.

FIGURE 14.5. Subdivision of a section.

As shown in Figure 14.5, each section may be further subdivided into smaller tracts, with north being to the top of the page and east to the right.

The fractions refer to the fraction of the section subdivision being considered and only 1/4 and 1/2 are used unless using lot numbers. The rectangular description of the section subdivisions begins with the smallest unit of area.

Problem: What are the descriptions of the subdivisions labeled A, B, and C in Figure 14.5?


B = N 1/2, SE 1/4, S23, T4N, R7E, Principal Meridian.

C = SW 1/4, SW 1/4, SW 1/4, S23, T4N, R7E, Principal Meridian.

The description for subdivision A is read as: "the northeast one quarter of section 23, located in township 4 north and range seven east of the Principal Meridian."

It is not unusual for a field to be contained in more that one fraction of a section. In these situations a "&" can be used to link the parts.

Problem: What is the description of the field in Figure 14.6?

Solution: NE1/4, SE1/4, NW1/4 & SW1/4,N, E1/4 see Figure 14.7.

Land descriptions also can be used to determine the acres contained in each subdivision. To determine the acres, divided the area of a section, 640 acres, by each of the denominators in the fractions.

FIGURE 14.7. Solution of fractions of section using an &.

Problem: What is the area (acres) for each of the subdivisions labeled A, B, and C in Figure 14.5?

Solution: Because a section is nominally 640 acres, the areas are:

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