The Ohio River Base surveys are made up of the Old Seven Ranges tract, the Ohio Company Purchase, Congress Lands North of the Old Seven Ranges, and Congress Lands East of the Scioto River. These surveys all use the Ohio River as their base line from which townships are counted moving northward, and continue the numbering of ranges westward from the Pennsylvania line. township numbering in these surveys can be confusing because adjacent townships in a row rarely share the same number designation due to the meandering of the Ohio River.
