Monument

A monument is the physical object that marks a surveyed corner on the ground. BLM's Glossary of Surveying and Mapping Terms defines it as "a physical structure, such as an iron post, marked stone or tree in place, which marks the location of a corner point established by a Cadastral Survey." To rank as a monument, an object "should have certain physical properties such as visibility, durability and stability, and they must define location without resorting to measurements."

The glossary adds that "monument" and "corner" are not synonymous. The corner is the point that the monument marks.

Legal weight

BLM's Manual of Surveying Instructions (2009) explains that the corners marked in an original survey "shall forever remain fixed in position, even disregarding technical errors that may have passed undetected before acceptance of the survey." Courts give evidence of the original corner position "far greater weight than the record relating to bearings and lengths of lines," and "the corner monument and its accessories constitute direct evidence of the position of the corner" (section 4-2).

Under 18 U.S.C. 1858, anyone who "willfully destroys, defaces, changes, or removes to another place any section corner, quarter-section corner, or meander post" on a government survey may be fined or imprisoned for up to six months (quoted in section 4-2).

What monuments are made of

• Prescribed monuments mark quarter-section, section, township, and meander corners, plus other corners the special instructions require (section 4-4)
• BLM uses regulation posts unless exceptional circumstances warrant other material (section 4-7)
• Native stone may substitute if authorized, durable, and at least 1,000 cubic inches in volume (section 4-10)

Each monument is backed by accessories, such as bearing trees, bearing objects, mounds of stone, memorials, or pits, so its position can be identified if the monument is destroyed or removed (section 4-79).

Monuments in descriptions

BLM's Specifications for Descriptions of Land (2017) use the word more broadly. In a metes-and-bounds description, a monument "may be either natural, such as a river, lake, rock ledge, tree, or ridge, or artificial, such as a wall, fence, ditch, road, marked stone, or post."

Monuments on mining claims

The Mining Law provides that a mining claim should be "distinctly marked by monuments on the ground" (30 U.S.C. 28, cited in Manual section 10-121). Where the location certificate and the ground disagree, the Manual states that the monuments are "controlling where there is a variation between the descriptive calls of the record and the monuments (30 U.S.C. 34)" (section 10-99). State statutes set the form. Arizona, for example, requires lode mining claim corners and end centers to be marked by posts projecting at least four feet above the ground or stone monuments at least three feet high (A.R.S. 27-204).

Why it matters in research

In mining claim research the questions are whether the monuments exist, whether they match the location notice and map, and which PLSS corners the mining claim is tied to.