Land Surveying Fundamentals and Boundary Law
This domain tests the evidentiary hierarchy that decides where a boundary legally lies, the doctrines that move a line without a deed (adverse possession, prescription, acquiescence, estoppel), and the PLSS and riparian rules Illinois surveyors apply daily.
Order of boundary evidence
Courts rank evidence: natural monuments (a river, a marked tree) beat artificial monuments (set iron, stone, concrete post); monuments beat calls for adjoiners; adjoiners beat courses and distances; distances beat area. A distance is only a description of what the surveyor intended to monument, so it never overrides a properly identified original corner.
Unwritten rights in Illinois
- Adverse possession: 20 years under 735 ILCS 5/13-101; possession must be actual, continuous, open and notorious, exclusive and hostile.
- A 7-year color-of-title claim requires payment of taxes.
- Prescriptive easement: 20 years of use; exclusivity is not required.
- Boundary by agreement or acquiescence: a disputed or uncertain line fixed by agreement and honored for roughly 20 years.
PLSS and riparian rules
The Third Principal Meridian governs most of Illinois, with its baseline near 38°28′ N; the Fourth Principal Meridian controls part of the west. Townships are 6 miles square, Section 1 sits in the northeast corner, and the north and west tiers are fractional. On non-navigable streams the boundary is the thread of the stream; on navigable waters the State holds the bed; accretion moves the line, avulsion does not.
Worked example
A deed runs "to an iron pin on the bank; thence N 10° E 500.00 ft to a stone." Both monuments are found undisturbed but measure 494.2 ft apart, and the computed area is 0.6 acre short. The monuments control: hold the found positions, report 494.2 ft as the measured distance, and note the record call. Area is the weakest evidence and never fixes a line.
Traps
A later-set monument that disagrees with the original record corner does not control, and a doubtful monument may be rejected. Do not treat accretion as avulsion, and do not confuse ownership of the bed with location of the boundary line.