How does land surveying draw precise borders over large scales? Let’s use the U.S. for an example. How did early settlers figure out state lines when there are no obvious landmarks back when the original boundaries were drawn? How did they determine the U.S. - Canadian border when there was no obvious reference point along much of it? Some of the western states have straight borders and no immediate difference in terrain. How did they draw the boundary and then figure out what it was again if there was a dispute that someone’s house was half way over the line?
Well, the US-Canada border west of the Great Lakes is supposed to follow the 49th parallel, which isn’t all that difficult to pinpoint using a variety of different methods. However, IIRC, I once read that in point of fact the border as actually surveyed deviates signifcantly from the 49t, so whatever technique they used, they didn’t use it very well.
There was a small town which IIRC was in West Virginia. When they re-surveyed a few years ago they found out that the town was actually in Virginia, which caused a huge controversy because the people who lived there did not want to become part of a different state.
A point is chosen as a reference or benchmark on which all surveys are based. For example the description of a boundry might read that it is from the “mouth of Smith’s Creek at Long x and Lat y in a straight line to a point 25 mi. SSW.” So, someone drives a stake, puts a nail in a tree, inscribes a mark on a rock or builds a survey monument and surveys from there. In that respect locations and boundries are a matter of definition. That is you define you starting point as some latitude, longitude and elevation relative to some defined mean sea level and base everything else on that.
In the case of where a house is, the location is surveyed from the benchmark in its legal description. If the parties to the dispute agree with the result of the survey it’s settled. Otherwise they go to court and a judge decides where it is.
Another good example of surveys that changed the border is Derby Line, Vermont. After an updated survey, it was found that the national border went right through town, dividing some people’s homes - it also divides a library/theater that was built after the fact.
I had a dream a couple days ago about a similar issue (yes, it was an unusual dream):
We know of various rivers that have changed their course, or eroded their left bank more than their right, etc. The state borders remain where they were at the time such borders were established, so sometimes you get a chunk of Illinois on the west side of the Mississippi.
My question is whether the same applies on land. In my dream, a mountain top which marked the border between two states was marked with a plaque marking the highest point in some state (Maine?). A couple feet away was a plaque marking the highest point in the next state (NH, if Maine was the first. I realize this is not possible for either state). Would such markers become inaccurate after a few decades, if the mountain moves a centimeter or so a year? Or is the border fixed to the position of the mountain, unlike rivers?
There was a rather large surveying error across much of the Tennessee-Kentucky border that was allowed to stand for years before it was corrected. When the correction occurred, it apparently caused more confuse than the original mistake, as people thought they had been born, married or loved ones buried in one state but they weren’t.
In general, once a political boundary is surveyed and monumented, it remains in effect even if it is wrong. Here is the most recent boundary treaty between the United States and Canada. Each article contains boilerplate language stating that
Note that post-1908 surveyors are instructed to respect the results from earlier surveys, and limit their activity to repairing damaged monuments and adding new ones to provide more detail:
Of course, in the case of really egregious errors, the countries or states concerned can always agree on a re-survey. Even then, however, they usually don’t. The aforementioned Vermont/Quebec border was surveyed so poorly that you can see its crookedness with a glance at any modern map. Even then, however,
As for the OP, a proper explanation of surveying would require a book. Check out Measuring America: How the United States was Shaped by the Greatest Land Sale in History for a start.
I worked at Distributed Proofreading www.pgdp.net on proofreading Letters and Papers of President …, and I remember whole sections about the New England - Canada boundry line, with letters back and forth between the US and UK, letters and reports from US, UK, & joint surveyors teams, etc. The orginal boundry after the Revolutionary War had been set based on “the highest point” and “drainage area of streams”, which turned out to be not in accordance with the actual land. It was rather interesting to read, and seemed to me to be a rather by-guess-and-by-gosh method used to fix the boundry.
I expect that series of books is now part of the freely available, downloadable library at Project Gutenberg (www.gutenberg.net .
Yes, you really need to read a book on surveying since it has been quite a complicated process. The first law pertaining to the survey of public lands was passed by the Congress of the Confederation in 1785. It provided for the survey of the “Western Territory” and authorized that territory to be divided into townships of six miles square, by lines running due north and south, and others crossing them at right angles. It was provided therein that the first line running north and south should begin on the Ohio River at a point due north from the western terminus f a line run as the south boundary of the state of Pa (the 1st principal meridian). The first line running east and west should begin at the same point and extend westerly through the whole territory (the first base line). The plats were marked showing the subdivision of the townships into sections one mile square, numbered from one to 36, commencing in the SE corner of the township and running from S to N. The direction was later changed so that the numbering began at the NE corner of the township.
The meridian lines are run 24 miles or the length of four twps to a standard parallel either N or S of the base line. Permanent corners are established every half mile on the meridians. (In 1908, Congress provided for the purchase of suitable metal monuments for marking the government corners: iron or steel of a designated size and sunk well into the earth.
The descriptions of land and plat of original survey filed in the Bureau of Land Management, as made by the chief cadastral engineer (using modern terminology) from the field notes, are conclusive, and the section lines and corners as laid down in the descriptions and plat are binding upon the Government and upon all parties concerned.
All of the original 13 colonies were the property of the British corwn, but by 1765, much of that land had passed into private hands by royal grants either to individuals or directly to the colonies and thence to individuals. But substantial areas were still crown lands. Under the terms of the Treaty of Ghent, all of this crown land became the property of the colony in which it was situated. None of these nor the state-owned lands in the present states of Maine, Ky, Tenn., and W. Va. were transferred to the national government by the blanket transfers when the US Constitution was adopted. All of these lands were described by metes and bounds and many were not too accurate or clear. Frequently no public records were made of transfers. Sometimes the grant was lost and individuals were holding such lands by virtue of their possession.
[source: * A Treatise on the Law of Surveying and Boundaries *, 4th edition by John S. Grimes, Esq., 1976, based on earlier editions by the late Frank Emerson Clark, Esq.]
An interesting trip is to the Von Schmidt Marker just South of Laughlin Nevada on river rd cuttoff.
The orig marker still stands, then about 70 feet East, the official, corrected survey marker lies.
When Nevada became a State about 140 plus years ago, the Von Schmidt survey team started from Nevadas Northwesternmost corner, and headed south with “chains” and early survey optics.
By the time the party reached the southwestern most tip of the state, they were only 70 feet off “to the left”. Amazing if ya think about it. The crossed the Sierras, Lake Tahoe, and other brutal terrain.
A few years back the Calif legislature granted the land to Nevada, because when the mistake was corrected, several Nevada Casino were in fact, in California, because of the 70 feet off from the Von Schmidt mistake.
My wife was an attorney in Las Vegas 15-ish years ago. As the town grew out into the desert, land that hadn’t been surveyed in a hundred years suddenly became valuable for housing tracts.
Two major brand-name builders (who hated each others’ guts) bought adjacent parcels of about a square mile apiece and began grading and leveling for construction of their latest marvels of soulless ticky-tack.
That’s when they discovered their parcels had an overlapping area about 100 yards wide and the length of their common border, nearly a mile. On paper, the plots were adjacent. On the ground, measured with modern tools from the definitional markers, they overlapped.
Oops.
Wife made a good living for a couple of years off of solving that one. Funny how neither party could see that splitting the difference and getting on with construction would have made them both a lot more money than idling all that capital for years to fight over who got 1 more row of houses. Heck, by trimming the lot sizes a smidgen they could both have fit just many houses in there as per their original plans. But noooo.
Human nature; it’s what lawyers depend on for job security.
As to rivers shifting course versus legal land boundaries …
There’s a legal distinction between gradual change, called “accretion”, and sudden change (ie after a flood or earthquake) called “avulsion”. I’m not the expert here, but IIRC, under accretion the border moves with the river, but under avulsion it remains where it was.
So around here, as the Mississippi slowly moves left or right from year to year, Illinios shrinks and Missouri grows in spots, or vice versa. But after a flood and the river settles into a new course, there may be political “islands” formed on the newly other side of the river.
One such political island is in north Omaha NE, where a chunk of Iowa was marooned on the west side of the current river course after an old near-loop in the river course broke through. http://www.mapquest.com/maps/map.adp?searchtype=address&country=US&addtohistory=&searchtab=home&address=&city=carter+lake+&state=ia&zipcode= and click zoom level 7.
The same logic applies to the landowners along the riverbank. Their owned parcel is constantly shrinking or growing as the river gradually moves. But if it jumps the banks, they may become a political island in themselves.
The law recognizes four distinct types of these changes: erosion, avulsion, accretion, and reliction. Avulsion is a sudden catastrophic change in the line or course of a stream or river or in the shore of a lke, pond, or sea. Accretion is the slow and imperceptible buildup of the river or stream bank or of the shore of a lake, pond, or sea due to deposit of sediment or alluvium. Reliction is the gradual, imperceptible withdrawal of water that has formed a natural boundary line. Avulsion does not result in a change of title to land. The boundary does, however, change both by accretion and reliction.
Where the accretion occurs due to natural causes, the riparian owner against whose bank the sediment is deposited acquires title to the alluvium so deposited against his shore. If the waters are navigable, the riparian owner’s title extends only to high water mark or low water mark. Title to the alluvium does not pass until it appears above the surface of the water, and title to islands appearing in the stream as a result of alluvium does not pass to the riparian owner u;nless, under the state law, title extends to the thread of the stream, even in the case of navigable streams. An Iowa case held that where such an island appeared in a navigable stream and there is a gradual buildup that connects the island with the shore, title to the entire mass is acquired by the owner of the shore if the buildup is from the shore to the island. Even where the stream is non-navigable and even where the riparian owner owns only to the bank and not to the center of the stream, he acquires title to all alluvium.
However, where the accretion is the result of artifical means, for example placing obstructions in a stream or lake, the riparian owner will not get title in most states. This resulted in the famous Chicago lawsuits which lasted over 50 years from Capt. Streeter, who had his boat on the shore of Lake Michigan. He claimed ownership to all the accretions and conveyed his interest by quit-claim deeds (conveying any and all interest that he had) to various speculators. Those accretions became very valuable land and is where part of Lake Shore Drive and environs is now located around Grand Ave. His claims were all finally held as “groundless.” 
Try Measuring America as a starting place on your reading list. 