The PLSS is held together by its corners. Every township, section, quarter-quarter and lot is defined by points that a surveyor established and monumented, and the whole system depends on being able to identify which kind of corner you have found. They are not interchangeable. Two corners a few feet apart on a standard parallel can control completely different pieces of land.
Before anything else, separate two words that are often used loosely. A corner is a point, a geometric location on the earth. A monument is the physical object placed to mark it. Monuments decay, are destroyed and are replaced; the corner they marked does not move.
Corner and monument
- Corner
- A point on a surveyed line at which an extremity of a boundary occurs, established by the original survey. The corner exists at the position the original surveyor gave it, whether or not anything now marks it.
- Monument
- The physical structure that marks a corner: a post, stone, iron pipe, brass-capped pipe, mound, or a natural object adopted for the purpose. The monument is evidence of the corner, not the corner itself.
This distinction sounds pedantic until a monument is found leaning, or found twice, or found where no corner should be. Once you separate the point from the object, the questions become answerable: is this object the original monument, does it stand where the original monument stood, and what corner was that monument set to mark?
The regular corners
| Corner | Where it was set | What it controls |
|---|---|---|
| Section corner | At each mile along township exteriors and interior subdivisional lines | The four sections that meet at that point |
| Quarter-section corner | At each half mile between section corners | The quarter lines and, through them, the subdivision of the two adjoining sections |
| Standard corner | On a base line, standard parallel, principal meridian or guide meridian at the time that line was run | The survey laid out from that line, which for a standard parallel means the survey to the north |
| Closing corner | Where a later survey line intersects a previously established governing line | Only the line that closed upon it; it says nothing about the survey on the other side |
| Meander corner | Where a survey line intersects the bank of a meanderable body of water | The ends of the meander traverse and the lot boundaries reaching the water |
| Special meander corner | On a meander line, between regular meander corners, to control an interior line reaching the water | That one subdivisional line |
| Witness corner | On a line leading to the true corner, at a measured distance, when the true point cannot be monumented | Nothing on its own; it perpetuates and references the true corner |
| Angle point | Where a surveyed boundary deflects, on irregular boundaries and reservation lines | The change of direction of that boundary |
Section and quarter-section corners are the backbone. In a regular township they occur every half mile along every subdivisional line, and between them they define every aliquot part that a description can name. Everything else in the table exists to handle a situation the regular pattern cannot.
Standard corners and closing corners
Along a standard parallel you will typically find two sets of corners in close proximity, and telling them apart is one of the sharper practical tests in PLSS work. The standard corners were set when the parallel itself was run, before the townships north of it existed. The closing corners were set later, when survey lines running north from the previous correction line arrived at the parallel.
Because meridians converge, the line arriving from the south does not reach the parallel at the standard corner. It arrives somewhere nearby, and the closing corner is set at that intersection. The two corners may be a few feet apart or a few hundred. The standard corner controls everything north of the parallel; the closing corner controls only the line that closed upon it, coming from the south.
Meander corners and water
When a subdivisional line reached the bank of a lake, a navigable river or tidewater, the surveyor did not continue across. He set a meander corner at the intersection of the line with the bank, recorded it, and later ran a meander traverse from one meander corner to the next along the shore in order to compute the area of the fractional parcels.
Meander corners are ordinary corners in the sense that they were monumented and recorded, and they are frequently the best surviving original evidence on the water side of a section. They are unusual in that the line they terminate does not end at a property boundary: the land normally runs on to the water itself. A special meander corner serves the same purpose for an interior line that reaches the water between the regular meander corners.
Witness corners and witness points
Sometimes the true corner position cannot carry a monument: it falls in a stream, in a marsh, on bare rock, in a roadway, or on a cliff face. In that case the surveyor set a witness corner on one of the lines leading to the true corner, at a recorded distance from it, and marked it as a witness corner. The true corner is at the recorded distance and bearing from the witness; the witness itself is not a boundary point.
- A witness corner is always on a line of the survey leading to the true corner, and its record states the distance to that corner.
- A monument marked as a witness corner is not the corner. Using it as one displaces the boundary by the witness distance.
- A witness point serves the same referencing purpose for a point on a line that is not itself a corner, such as a point on a meander line.
- Recovering a witness corner is often enough to make an otherwise lost corner merely obliterated, because the true position can be recomputed from the record.
- Two or more witness corners on different lines fix the true corner by intersection and are stronger evidence than one.
Corners the original survey never set
Not every corner named in a description exists as an original corner. The center of a section was not monumented in the original survey; it is established afterwards at the intersection of the straight lines joining opposite quarter corners. The quarter-quarter corners, sometimes called sixteenth corners, were likewise not set in the ordinary original subdivision, except along the north and west tiers of a township where lotting required them.
This is a crucial distinction for evidence. An original corner, once identified, is conclusive and cannot be moved by measurement. A corner established later by a local surveyor subdividing a section is not original: it is a correct or incorrect application of the subdivision rules to the original corners, and its standing depends on the rules, on how long it has been relied upon, and on the doctrines that govern boundaries between adjoining owners.