Some legal descriptions are very simple and involve a Lot and a Block and a Subdivision name. Even those can be wrong when verified by surveying equipment. To make certain that you own a piece of property, it's a good idea to buy a title insurance policy. You will mostly find Lot and Block legal descriptions within city boundaries.
A more common legal description is metes and bounds. This involves using the public surveying system, which starts from when the United States issued its patent. It uses townships and ranges. Land is divided into sections, and each section is 640 acres. The legal description pinpoints the location of the subject property within its particular Township, Range and Section, which might also involve degrees and distance.