In 1784, Thomas Jefferson proposed a new system of measuring land by "square tracts" rather the traditional system of "metes and bounds". This was eventually turned into the "Land Ordinance of 1785". Through this measure Ohio became the experimental site of the new public land surveying and sale system. I ran across the following webpage describing the history of how Ohio land grants and measurements were made, with references to specific ordinances and districts that were enacted and affected Ohio. Introduction to Ohio Land History http://www.ultranet.com/~deeds/ohio.htm