How is a section defined in the rectangular government survey system?

In the rectangular government survey system, a section is defined as a one-square-mile square of land, which corresponds to an area of 640 acres. This method of land description divides land into townships, which are further subdivided into sections. Each section measures one mile on each side, thereby forming a square. This system is commonly used in the United States to simplify the identification and mapping of parcels of land, especially in rural areas.

Other options provided do not align with the established definitions within this survey system. For instance, a plot of 40 acres may refer to a smaller parcel, while a city block can vary greatly in size depending on urban design. Additionally, a quarter of an acre is a fraction of a section and further illustrates the importance of understanding the basic measurements in land surveying, but does not accurately embody the definition of a section.