Its eastern terminus is in northern Belpre at an interchange with SR 7.

All of SR 618 runs through the southwestern portion of Washington County.

The NHS is a system of routes deemed to be most important for the economy, mobility and defense of the country.

SR 618 was routed onto its present alignment, while US 50 and SR 7 was moved onto the former alignment of SR 618, which was widened into a four-lane divided highway simultaneous to the alignment swap.

[5][6] The entire route is in Washington County.