Old Mountain Road is the original road connecting Raglan to the Waikato until SH23 was constructed. Now the road is little used except for local farmers and residents. The gravel on the road can be thick in places especially if it has recently been graded, and the road has many tight, blind, and quite steep corners especially at the Hamilton end.

In World War 2 Home Guard troops built a tank trap in a narrow section of the road to act as a barrier and deterrent to an invading force should one land at Raglan and try to move inland, this is still in place today.

The West end of Old Mountain Road links into Waitetuna Valley Road.