Its northern terminus is at SR 103 nearly 1.75 miles (2.82 km) east of Willard.

SR 598 is not included as a part of the National Highway System (NHS).

The NHS is a network of routes identified as being most important for the economy, mobility and defense of the nation.

[4] The highway was originally routed along its present alignment from its southern terminus in Galion to its junction with SR 98 northeast of Tiro.

[8] Media related to Ohio State Route 598 at Wikimedia Commons