 No part of SR 589 is included as a part of the National Highway System, a system of routes considered to be most important for the economy, mobility and defense of the nation.When it was designated in 1937, SR 589 appeared only along its current northern segment between US 36 east of Fletcher and its current northern terminus at what was then designated SR 54 (now SR 29).One year later, SR 589 was extended westerly from its previous southern terminus along US 36 to Fletcher, then south to its current southern terminus at SR 55 in Casstown.