Public Land Survey System and State-Specific Law
What this domain tests
This is the mechanical heart of the exam: township and section structure, corner identification, subdivision of sections, and reestablishment of lost corners, plus the New Mexico statutes that govern practice and recording.
Core rules
- Most of New Mexico is referenced to the New Mexico Principal Meridian, whose initial point lies south of Socorro near San Acacia; the base line runs east and west from it.
- Townships are nominally 6 miles square, divided into 36 sections of 640 acres, numbered serpentine from section 1 in the northeast corner to 36 in the southeast.
- Standard parallels (correction lines) are run generally every 24 miles, with guide meridians closing the blocks; convergence and correction produce fractional lots and double corners in the north and west tiers.
- Lost corners are reestablished by proportion, not by guessing: single proportion along a line between existing corners, double proportion where two directions must be restored. Follow the current BLM Manual of Surveying Instructions.
- New Mexico practice is regulated under NMSA Chapter 61, Article 23; plats and surveys intended for recording go to the county clerk, and plats must carry the seal, signature, date, and license number.
Worked example
A quarter-section corner on a line between two found section corners is lost. Measured distance between the found corners: 5,283.4 ft. Record: 40.00 chains from each end, total 80.00 chains. Position = 5,283.4 × (40/80) = 2,641.7 ft from either corner. Reasoning: single proportion divides the measured distance in the ratio of the record distances; it does not simply bisect the line or hold a record distance.
Traps that cost marks
- Proportioning a corner that is not actually lost.
- Ignoring double corners at standard parallels.
- Subdividing a section by area instead of aliquot parts.
- Assuming a quarter corner sits at the geometric midpoint of the section line.
- Sealing a plat you did not prepare or supervise.