Boundary Law and Legal Principles of Real Property
Title versus location
Boundary law separates ownership (title) from the physical location of the line. A surveyor resolves location, not title, and must know the interests that affect a boundary: fee simple, easements appurtenant and in gross, profits, licenses, and prescriptive easements, which require open, notorious, adverse, continuous use for the statutory period. Adverse possession adds color of title, payment of taxes, and in most states ends only with a quiet-title judgment. Long occupancy alone does not move a record line.
Boundary by agreement and practical location
Where the true line is uncertain, adjoining owners may fix it by agreement plus acquiescence over a substantial period. Practical location applies where a monument is lost or doubtful and the parties have long treated a line as the boundary.
Water boundaries and senior rights
Accretion (gradual and imperceptible) adds to the riparian or littoral owner's land; avulsion (sudden change) does not. Reliction and erosion follow the same gradual logic. Among private parties, the first conveyance out of common ownership is senior and controls; the junior deed takes only what the senior left.
Traps in questions
Equating long possession with ownership; importing another state's statutory period or elements; treating an easement as fee ownership; calling a storm-caused channel change accretion; assuming a boundary agreement binds absent uncertainty.
Rule of thumb
The senior grant carries the land and the junior grant carries the litigation. Ask who conveyed first, and whether any line was ever adjudicated.