In land survey grids, what is the east-west line called?

In land survey grids, the east-west line is known as the Baseline. This line is fundamental to the rectangular survey system, which divides land into townships and ranges. The Baseline runs horizontally and serves as a reference point from which townships are numbered north and south. Townships are further subdivided into sections, which are the basic units of land measurement.

Understanding the role of the Baseline is crucial in land surveying, as it provides a systematic way to describe locations and lay out land systematically within the grid. This contrasts with other terms in the question, such as Principal Meridian, which refers to the north-south line used in conjunction with the Baseline to define areas in the rectangular survey system. Range Lines run parallel to the Principal Meridian and are used to create columns of townships, while Township Lines are the horizontal lines that define the boundaries of these townships north and south of the Baseline.