When buying or selling property, the size and exact boundaries of the property are important determinants to its price. While the address may provide a location, it says nothing about the size or boundaries of the property. Deeds and sales contracts require a legal description that is legally sufficient to identify the property and its boundaries and that would allow a surveyor to locate the property and its boundaries with precision.
There are 3 independent methods that can be used to determine the exact location and boundaries of a parcel of land: metes and bounds, rectangular survey, and lot and block.
A metes and bounds description uses lengths and angles of boundaries starting at the point of beginning (POB). Starting at the POB, the length of each boundary is described and the angle that it forms with the previous boundary. This continues to the point of end (POE), which is identical to the point of beginning, since all properties have closed boundaries.
Of course, for a metes and bounds description to be legally sufficient, the location of the POB must be specified, and is usually specified by a monument (aka landmark), which can be a large object or other stable structure, including rocks, trees, streams, railroads, roads, and intersections that are recorded by surveyors to locate property. Nowadays, many monuments are iron pins or concrete posts installed by surveyors or by the U.S. Corp of Engineers. The actual placement of the monuments is more important than the lengths and angles specified in the legal description, since the property’s boundaries must form a closed area.
The rectangular survey system (aka government survey system), was specified by Congress in 1785 to mark large tracts of land that the United States received in its early years, including the Northwest Territory. The rectangular survey system specifies locations by using a rectangular coordinate system—hence, the name—that consists of principal meridians that run north and south and indicate longitude, and base lines that run east and west and indicate latitude. Principal meridians and base lines partition the land into quadrangles, which are squares of land with each side measuring 24 miles. These quadrangles are further subdivided in 16 townships, with each side of a township measuring 6 miles and covering an area of 36 square miles. Townships are further subdivided into 36 1-square mile sections, with each section equal to 640 acres. In many states, the rectangular survey system is supplemented with a mete-and-bounds description to describe small parcels of land.
The other system of legal description is the lot-and-block system (aka recorded plat system), which refers to specific parcels of land by their lot number or letter and the block, or subdivision plat, in which the lot is located. The block itself is located by using either the metes and bounds system or the rectangular survey system. To identify a particular parcel of land, the lot-and-block system specifies the lot and block number, the name or number of the subdivision plat, and the name of the county and state.