Cadastral and Public Land Survey System (PLSS)
Oklahoma has a dual cadastral fabric: PLSS coverage across the former Oklahoma Territory and much of the west, and allotment and metes-and-bounds boundaries across much of the former Indian Territory in the east. The Indian Meridian initial point lies near Davis in Murray County; the Cimarron Meridian governs the panhandle, with its initial point at 36°30' N, 103° W on the New Mexico line.
Sections and aliquot parts
A normal township is six miles square, containing 36 sections of nominally 640 acres, numbered boustrophedon from the northeast corner. Halving gives 320, 160, 80, 40, 20, and 10 acres. Fractional lots along north and west tiers absorb the excess or deficiency of the township.
Retracement
Original corners and their accessories (bearing trees, mounds, stones) are the best evidence. A lost corner is restored by proportionate measurement between accepted corners, not by record distance alone. Closing corners and double corners occur where township lines were run as closing lines; they are not interchangeable with standard corners.
Worked example
A quarter-section corner is lost between accepted section corners 5,280.00 ft and 5,286.00 ft apart. Proportionate position = 5,280.00 + (5,286.00 − 5,280.00)/2 = 5,283.00 ft from the west corner. Setting the corner at 2,640.00 ft would ignore the section's actual dimension.
Traps
Assuming every section is 5,280 ft square; treating a closing corner as a standard corner; using record distance instead of proportion; applying PLSS rules to Indian Territory allotments that were never sectionized; ignoring the difference between a quarter-section corner and a quarter-quarter corner.