The Ordinance of 1785 provided that the public lands of the United States be divided by lines intersecting true north and at right angles to form townships and ranges - both six miles square. The townships and ranges were to be marked with progressive numbers from the beginning, or "initial" point that was surveyed in a given area. Such townships and ranges were to be divided into thirty-six sections, each one mile square and containing 640 acres. The sections were to be numbered respectively, beginning with the number one in the northeast section and proceeding west and east alternately through the township with progressive numbers to thirty-six.
Note that townships are counted north-south of the initial point, while ranges are counted east-west.
In order to complete this type of surveying task, it was necessary to establish independent initial points to serve as bases for surveys. Principal meridians (north-south lines) and baselines (east-west lines) were then surveyed from these initial points. Guide meridians were initiated at baselines, and standard parallels were initiated at principal meridians to form townships.
In Idaho the Initial Point is located about 8 miles south of Kuna. It is a volcanic hill that was precisely located on April 19, 1867. Peter W. Bell used stellar observations to locate the point, by order of Lafayette Cartee, the first surveyor general of Idaho Territory. The Initial Point is marked with a small, round brass marker (about the size of a jam jar lid), and the hill is visible for miles around.
The principal meridian for Idaho is the exact north-south line as measured at Initial Point. It was called the Boise Meridian, and it runs the entire length of Idaho - from the Nevada border to the border with British Columbia.
The city of Meridian was named for the Boise Meridian as it lies exactly north on the surveyors line.All surveys conducted in Idaho which divided the almost 54 million acres of unmapped lands are based from Initial Point.