Final answer:
The Rectangular Survey System, or Public Land Survey System, is a method of dividing land into townships and sections in the United States, with townships being the basic unit and subdivided into sections of 640 acres.
Step-by-step explanation:
The Rectangular Survey System, also known as the Public Land Survey System (PLSS), is a method used to divide and describe land in the United States. The basic unit of this grid system is the township, which is a square parcel of land six miles on each side. Townships are further subdivided into 36 one-square-mile sections, each of which is 640 acres. These sections can be subdivided into quarter sections (160 acres) and quarter-quarter sections (40 acres). Larger parcels were more common in drier climates where ranching was more prevalent than farming.
The system was a result of the Ordinance of 1785 which called for the division of land into rectangular plots to make government land sales easier. This method contrasts with the metes and bounds system, which was more arbitrary in the shape and size of land parcels, using local landmarks as references.