Assessing property boundaries is both an art and a science.
Disputes regarding property boundaries can arise for a number of 
reasons. Properties can be difficult to survey. Rough terrain and human error may lead to miscalculation. Older boundaries may have been determined with poor instrumentation.
One common boundary-related problem occurs when a gap of land–known in the surveying industry as a hiatus–is found between properties and does not belong to either party. These gaps, as well as boundary overlaps, tend to occur when properties are resurveyed and discrepancies are found in either a subsequent survey (the junior survey) or with the original survey (the senior survey).
The federal courts have settled many property boundary disputes. Over time, established procedures have evolved for resolving these discrepancies.
In U.S. v. Weyerhaeuser Company (1967), the 9th Circuit Court decided that discrepancies in surveys did not matter and that the original monuments– the permanently placed survey markers in the ground–marked the boundary, and any resulting hiatus was deemed public land. The courts have consistently determined that hiatus land shall remain in the public domain.
Cases regarding overlaps are more complicated. Courts have consistently said that when two officially accepted surveys conflict, and the result is an overlap, the survey that is senior in time takes precedent.
When it comes to court cases involving property rights, the concept of “first in time, first in right” is firmly established. In Wirth v. Branson (1878), the U.S. Supreme Court made it clear that once a property had been patented (title of ownership confirmed by the government) the government cannot convey that land to any second party.
The information contained in this article is educational and intended for informational purposes only. It does not constitute real estate, tax or legal advice, nor does it substitute for advice specific to your situation. Always consult an appropriate professional familiar with your scenario.
