The Treaty of Greenville in 1795 established a line across northern Ohio then from Fort Recovery southwest to the mouth of the Kentucky River. Surveyors at the time marked the line by noting large rocks, or by cutting blazes in large trees.
Only a couple roads in the county follow parts of this line — Salisbury, Flatley, and Boundary Roads.
On Boundary Road, northeast of Fountain City, is a Burr Oak tree that could be one of the original trees. No one has been able to prove definitively that it is one of the original blazed trees, but it is old enough and in a likely position.