Interesting that this thread just came up. My neighbor who's moving out of State would love it if Adverse Posession could clean up a problem he found when putting his house up for sale.
He started with a survey, and that's when the problem was found.
House sits on 4 acres in a subdivision. Many (unknown) years ago before he purchased the house, the neighboring house owner accidentally "squared off" a portion of the property.
Imagine if you will, lots that are four acres in basically pie slice shapes, but not to a point. Chop off the point in the back for a path that runs behind them all.
His former neighbor squared the line to the road and built his fence along it. His fence at the rear/tip of the pie is at the property line marker. At the street side, he came straight forward instead of the angle needed to make the pie shape.
Cut off about 1/4 acre.
The former neighbor even moved his fence back from what he thought was the easement and horse trail required between the properties. Therefore moving the horse trail over.
Total encroachment at the front? 53'. The fence, horse trail, signage for the horse trail, etc... All wrong as long as the guy selling has lived there, which is 12 years.