The township is the basic building block of the PLSS. In its normal form it is a block of land six miles square, containing thirty-six sections of one mile square each, laid off from the principal meridian and base line of its survey system. A township designation such as T3N, R2W, of the 6th Principal Meridian is a complete address for that block within its system.
The word township carries two meanings in the United States and they cause endless confusion. A survey township is the six-mile block described here. A civil township is a unit of local government, which in some states happens to coincide with survey townships and in others does not. This article is about the survey township only.
Tiers, ranges, and the coordinate pair
- Township (tier)
- A row of townships extending east and west, numbered consecutively north or south from the base line. Township 3 North means the third such row north of the base line.
- Range
- A column of townships extending north and south, numbered consecutively east or west from the principal meridian. Range 2 West means the second such column west of the meridian.
The two numbers together identify one township, in the same way a row and a column identify one cell of a spreadsheet. Counting starts at one in each direction, immediately adjacent to the controlling line, and the direction letter says which side of the line you are on. Township 1 North touches the base line from the north; Township 1 South touches it from the south. The same is true for Range 1 East and Range 1 West either side of the principal meridian.
A useful mental check is to translate a designation into a distance. Since a normal township is six miles across, T3N, R2W places the township roughly between twelve and eighteen miles north of the base line and between six and twelve miles west of the principal meridian. Roughly, because standard parallels, guide meridians and the accumulated irregularity of the original surveys all disturb the arithmetic.
Reading and writing a designation
Designations are written in several equivalent styles, and all of them mean the same thing. The elements are the township number with its direction, the range number with its direction, and the governing principal meridian.
| Written form | Reads as |
|---|---|
| T3N, R2W, 6th P.M. | Township 3 North, Range 2 West, of the Sixth Principal Meridian |
| T. 3 N., R. 2 W. | The same, in the punctuation style used on federal plats |
| 3N 2W | An abbreviated index form; ambiguous unless the meridian is supplied elsewhere |
| T3N R2W S14 | The same township with section 14 appended |
What a normal township contains
A normal township is six miles on a side. In the units of the original surveys, where the chain of 66 feet was the working measure, that is 480 chains on a side. The interior is divided into thirty-six sections, each nominally one mile square, and each nominally 640 acres.
6 mi = 480 ch = 31,680 ft and 1 mi = 80 ch = 5,280 ft36 sections × 640 acres = 23,040 acres per normal townshipThe word nominal is doing real work in those sentences. Almost no township on the ground closes at exactly 480 chains, because the original chaining had error in it, because slope and vegetation made measurement hard, and because meridians converge so the north boundary of a township is genuinely shorter than the south boundary. The PLSS handles all of this by deciding in advance where the discrepancy will be put, rather than by pretending it does not exist.
Fractional and irregular townships
Not every township is normal. A township is fractional when part of it is missing, and irregular when its shape or interior departs from the standard pattern. Common causes include the following.
- A large body of water or a navigable river cuts through the township, so the sections it touches were meandered and returned as fractional with government lots instead of full quarter-quarters.
- The township lies against the boundary of another survey system, a state line, or a prior land grant, so its sections close against that line with fractional widths.
- The township abuts a standard parallel from the south, where the guide meridians of the block close against the correction line and produce a row of closing corners.
- The original survey was never completed, leaving unsurveyed interior areas that were later covered by a dependent resurvey or a supplemental plat.
In every one of these cases the official plat is the authority on what the township actually contains. Never assume from the designation alone that a township has thirty-six full sections or that section 14 contains 640 acres. Read the plat and the field notes first.
Using township designations in practice
For record research, the township is the natural index unit: federal plats, field notes, and most county land records in public-land states are filed by township and range. For fieldwork, the township is the natural unit of control, because the township exterior boundaries were run and monumented before the interior was subdivided, and therefore usually carry the best and oldest evidence available.
That ordering matters when a corner has to be restored. The exterior boundaries of a township control the interior subdivision, not the other way round. A retracement typically begins by recovering the township exterior corners, then works inward to the section corners that depend on them.