What is the name of the line that is marked by monuments running north and south, used in public land surveys?

The line marked by monuments running north and south in public land surveys is known as the Principal Meridian. These Principal Meridians are fundamental in the rectangular system of land description, serving as reference points in a given area used for plotting out townships and sections in land surveys. Each Principal Meridian is typically designated based on the location of the survey and has several Guide Meridians and Baselines that relate to it.

The Principal Meridian establishes the baseline for measurements that occur to the east and west, while ensuring that all surveys are consistently referenced back to a primary point. This is crucial in maintaining consistency and accuracy in land surveying, especially in large areas and various townships.

The Guide Meridian, while related, refers specifically to the perpendicular lines that run north and south of the Principal Meridian at set intervals, helping to define the boundaries of townships in that region. Understanding these terms and their relationships is essential for anyone working within the field of land surveying.