After the founding of the original thirteen colonies, the United States expanded westward rapidly. And with the vision of Thomas Jefferson and some of the other early survey fathers, the Public Land Survey System under the General Land Office completed the largest subdivision of land ever - almost all of the lands west of the Mississippi, north of the Rio Grand, and south of the Canadian border (and some parts north too), were broken into more or less regular squares of one mile by one mile.
The men and women who performed this task followed standard instructions and systematically left evidence of the lines they walked, hacked, climbed and surveyed. Generally, monuments to the lines were left every half mile with occasional additional ties to physical features such as line trees, rivers, buildings and roads. Often, the monuments were perpetuated as settlers built fences or other improvements near their property boundaries. Whether perpetuated or not, the monuments fell victim to age and the ravages of time. A hundred plus years on, it is unusual to find original evidence and this fact makes it imperative that modern Surveyors take their role seriously in preserving and leaving evidence to last another hundred years.
The surveyor…must inquire into all the facts (evidence), giving due prominence to the acts of parties concerned, and always keeping in mind, first, that neither his opinion nor his survey can be conclusive upon parties concerned, and, second, that courts and juries may be required to follow after the surveyor over the same ground, and that it is exceedingly desirable that he govern his action by the same lights and the same rules that will theirs.
C. Justice Thomas Cooley, Michigan Supreme Court ca. 1880