The Adverse Possession Law in Idaho basically states that if you think you own property to the fenceline, actively tend to maintaining the property to that fenceline (i.e. grazing, logging, farming), then you essentially own the property to the fenceline. The length of ownership required to make a claim on the property if someone has a dispute or disagreement with the location of the fenceline has been quoted as 5 to 7 years.
Common boundary line verbal agreements have gone on in the west for many years. Fences were placed where ownerships were thought to be or where placing a fenceline made the most sense, not according to actual/legal boundary lines. In the past, these lines have been either graciously accepted or met with feuds and fights that have ended in personal or legal battles.
In 2004, the Idaho legislature looked at changing the Adverse Possession law to reflect the current changing land ownership patterns. Much of the west is sub-dividing at an accelerating rate. Smaller ownerships with homes scattered throughout the rural west have required more legal surveys and property line establishment than ever before. If a parcel of land is purchased with a legal survey and the adjacent neighbor is infringed on with the survey, then through adverse possession, the prior line could take precedent and the new owner may be out of luck. Adverse possession stands up even if the adjacent landowner has not been paying taxes on the portion of land now identified by the survey. This is not as simple as it sounds,however, because if a line is off on the north boundary of the property where is it on the south end? Maybe there was or are compensating errors or maybe not. Is the Adverse Possession law good or bad? The answer to this question depends on which side of the fence you own. The new law considered grandfathering all earlier boundaries, and the surveys for new property owners would now stand. The law was tabled until next year.
On boundaries not legally surveyed, a written boundary line agreement between adjacent property owners is a good idea, one that has been drafted by an attorney and recorded at the courthouse. This will at least make a strong position and will show up on a title search if the land exchanges hands.