43 U.S.C. § 751: Rules of survey

The public lands shall be divided by north and south lines run according to the true meridian, and by others crossing them at right angles, so as to form townships of six miles square, unless where the line of an Indian reservation, or of tracts of land surveyed or patented prior to May 18, 1796 , or the course of navigable rivers, may render this impracticable; and in that case this rule must be departed from no further than such particular circumstances require. Second. The corners of the townships must be marked with progressive numbers from the beginning; each distance of a mile between such corners must be also distinctly marked with marks different from those of the corners. Third. The township shall be subdivided into sections, containing, as nearly as may be, six hundred and forty acres each, by running parallel lines through the same from east to west and from south to north at the distance of one mile from each other, and marking corners at the distance of each half mile. The sections shall be numbered, respectively, beginning with the number one in the northeast section and proceeding west and east alternately through the township with progressive numbers, until the thirty-six be completed. Fourth. The deputy surveyors, respectively, shall cause to be marked on a tree near each corner established in the manner described, and within the section, the number of such section, and over it the number of the township within which such section may be; and the deputy surveyors shall carefully note, in their respective field books, the names of the corner trees marked and the numbers so made. Fifth. Where the exterior lines of the townships which may be subdivided into sections or half-sections exceed, or do not extend six miles, the excess or deficiency shall be specially noted, and added to or deducted from the western and northern ranges of sections or half-sections in such township, according as the error may be in running the lines from east to west, or from north to south; the sections and half-sections bounded on the northern and western lines of such townships shall be sold as containing only the quantity expressed in the returns and plats respectively, and all others as containing the complete legal quantity. Sixth. All lines shall be plainly marked upon trees, and measured with chains, containing two perches of sixteen and one-half feet each, subdivided into twenty-five equal links; and the chain shall be adjusted to a standard to be kept for that purpose. Seventh. Every surveyor shall note in his field book the true situations of all mines, salt licks, salt springs, and mill-seats which come to his knowledge; all watercourses over which the line he runs may pass; and also the quality of the lands. Eighth. These field books shall be returned to the Secretary of the Interior or such officer as he may designate, who shall cause therefrom a description of the whole lands surveyed to be made out and transmitted to the officers who may superintend the sales. He shall also cause a fair plat to be made of the townships and fractional parts of townships contained in the lands, describing the subdivisions thereof, and the marks of the corners. This plat shall be recorded in books to be kept for that purpose; and a copy thereof shall be kept open at the office of the Secretary of the Interior or of such agency as he may designate for public information, and other copies shall be sent to the places of the sale, and to the Bureau of Land Management. The Secretary of the Interior shall conduct an assessment of the need for and cost and benefits associated with improvements in the existing methods of land surveying and mapping and of collecting, storing, retrieving, disseminating, and using information about Federal and other lands. the Secretary of Agriculture; the Secretary of Commerce; the Director of the National Science Foundation; representatives of State and local governments; representatives of private sector surveying and mapping science. No later than one year after the day of enactment of this Act [ Aug. 20, 1988 ], the Secretary of the Interior shall report to the Congress concerning the results of the assessment required by this section. relevant recommendations made by the National Academy of Sciences (National Research Council) on the concept of a multipurpose cadastre from time to time prior to the date of enactment of this Act [ Aug. 20, 1988 ]; ongoing activities concerning development of an overall reference frame for land and resource information, including but not limited to a geodetic network, a series of current and accurate large-scale maps, cadastral overlay maps, unique identifying numbers linking specific land parcels to a common index of all land records in United States cadastral systems, and a series of land data files; ways to achieve better definition of the roles of Federal and other governmental agencies and the private sector in dealing with land information systems; ways to improve the coordination of Federal land information activities; and model standards developed by the Secretary for compatible multipurpose land information systems for use by Federal, State and local governmental agencies, the public, and the private sector. The report required by subsection (c) may also include such recommendations for legislation as the Secretary of the Interior considers necessary or desirable.”