[Note 1] Route 189 connects with the main gate of Marine Corps Air Station Iwakuni at the southernmost end, and with the Taiteishi intersection of Routes 2 and 188.

[6] Until 2010 the official end-point of Route 189 lay within the US military base at Iwakuni, causing road management and maintenance issues as the general public have no access.

This was due to the original designation stating that the road ended before the platform where the national flag was hoisted, inside the main gate.

[7] In 2010 this was changed, with the road now officially ending at the main gate of the base.

This article relating to the roads and highways in Japan is a stub.